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OpenCloudOS-Kernel/fs/ext4/inode.c

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/*
* linux/fs/ext4/inode.c
*
* Copyright (C) 1992, 1993, 1994, 1995
* Remy Card (card@masi.ibp.fr)
* Laboratoire MASI - Institut Blaise Pascal
* Universite Pierre et Marie Curie (Paris VI)
*
* from
*
* linux/fs/minix/inode.c
*
* Copyright (C) 1991, 1992 Linus Torvalds
*
* Goal-directed block allocation by Stephen Tweedie
* (sct@redhat.com), 1993, 1998
* Big-endian to little-endian byte-swapping/bitmaps by
* David S. Miller (davem@caip.rutgers.edu), 1995
* 64-bit file support on 64-bit platforms by Jakub Jelinek
* (jj@sunsite.ms.mff.cuni.cz)
*
* Assorted race fixes, rewrite of ext4_get_block() by Al Viro, 2000
*/
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/time.h>
#include <linux/jbd2.h>
#include <linux/highuid.h>
#include <linux/pagemap.h>
#include <linux/quotaops.h>
#include <linux/string.h>
#include <linux/buffer_head.h>
#include <linux/writeback.h>
#include <linux/mpage.h>
#include <linux/uio.h>
#include <linux/bio.h>
#include "ext4_jbd2.h"
#include "xattr.h"
#include "acl.h"
/*
* Test whether an inode is a fast symlink.
*/
static int ext4_inode_is_fast_symlink(struct inode *inode)
{
int ea_blocks = EXT4_I(inode)->i_file_acl ?
(inode->i_sb->s_blocksize >> 9) : 0;
return (S_ISLNK(inode->i_mode) && inode->i_blocks - ea_blocks == 0);
}
/*
* The ext4 forget function must perform a revoke if we are freeing data
* which has been journaled. Metadata (eg. indirect blocks) must be
* revoked in all cases.
*
* "bh" may be NULL: a metadata block may have been freed from memory
* but there may still be a record of it in the journal, and that record
* still needs to be revoked.
*/
int ext4_forget(handle_t *handle, int is_metadata, struct inode *inode,
struct buffer_head *bh, ext4_fsblk_t blocknr)
{
int err;
might_sleep();
BUFFER_TRACE(bh, "enter");
jbd_debug(4, "forgetting bh %p: is_metadata = %d, mode %o, "
"data mode %lx\n",
bh, is_metadata, inode->i_mode,
test_opt(inode->i_sb, DATA_FLAGS));
/* Never use the revoke function if we are doing full data
* journaling: there is no need to, and a V1 superblock won't
* support it. Otherwise, only skip the revoke on un-journaled
* data blocks. */
if (test_opt(inode->i_sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA ||
(!is_metadata && !ext4_should_journal_data(inode))) {
if (bh) {
BUFFER_TRACE(bh, "call jbd2_journal_forget");
return ext4_journal_forget(handle, bh);
}
return 0;
}
/*
* data!=journal && (is_metadata || should_journal_data(inode))
*/
BUFFER_TRACE(bh, "call ext4_journal_revoke");
err = ext4_journal_revoke(handle, blocknr, bh);
if (err)
ext4_abort(inode->i_sb, __func__,
"error %d when attempting revoke", err);
BUFFER_TRACE(bh, "exit");
return err;
}
/*
* Work out how many blocks we need to proceed with the next chunk of a
* truncate transaction.
*/
static unsigned long blocks_for_truncate(struct inode *inode)
{
ext4_lblk_t needed;
needed = inode->i_blocks >> (inode->i_sb->s_blocksize_bits - 9);
/* Give ourselves just enough room to cope with inodes in which
* i_blocks is corrupt: we've seen disk corruptions in the past
* which resulted in random data in an inode which looked enough
* like a regular file for ext4 to try to delete it. Things
* will go a bit crazy if that happens, but at least we should
* try not to panic the whole kernel. */
if (needed < 2)
needed = 2;
/* But we need to bound the transaction so we don't overflow the
* journal. */
if (needed > EXT4_MAX_TRANS_DATA)
needed = EXT4_MAX_TRANS_DATA;
return EXT4_DATA_TRANS_BLOCKS(inode->i_sb) + needed;
}
/*
* Truncate transactions can be complex and absolutely huge. So we need to
* be able to restart the transaction at a conventient checkpoint to make
* sure we don't overflow the journal.
*
* start_transaction gets us a new handle for a truncate transaction,
* and extend_transaction tries to extend the existing one a bit. If
* extend fails, we need to propagate the failure up and restart the
* transaction in the top-level truncate loop. --sct
*/
static handle_t *start_transaction(struct inode *inode)
{
handle_t *result;
result = ext4_journal_start(inode, blocks_for_truncate(inode));
if (!IS_ERR(result))
return result;
ext4_std_error(inode->i_sb, PTR_ERR(result));
return result;
}
/*
* Try to extend this transaction for the purposes of truncation.
*
* Returns 0 if we managed to create more room. If we can't create more
* room, and the transaction must be restarted we return 1.
*/
static int try_to_extend_transaction(handle_t *handle, struct inode *inode)
{
if (handle->h_buffer_credits > EXT4_RESERVE_TRANS_BLOCKS)
return 0;
if (!ext4_journal_extend(handle, blocks_for_truncate(inode)))
return 0;
return 1;
}
/*
* Restart the transaction associated with *handle. This does a commit,
* so before we call here everything must be consistently dirtied against
* this transaction.
*/
static int ext4_journal_test_restart(handle_t *handle, struct inode *inode)
{
jbd_debug(2, "restarting handle %p\n", handle);
return ext4_journal_restart(handle, blocks_for_truncate(inode));
}
/*
* Called at the last iput() if i_nlink is zero.
*/
void ext4_delete_inode (struct inode * inode)
{
handle_t *handle;
truncate_inode_pages(&inode->i_data, 0);
if (is_bad_inode(inode))
goto no_delete;
handle = start_transaction(inode);
if (IS_ERR(handle)) {
/*
* If we're going to skip the normal cleanup, we still need to
* make sure that the in-core orphan linked list is properly
* cleaned up.
*/
ext4_orphan_del(NULL, inode);
goto no_delete;
}
if (IS_SYNC(inode))
handle->h_sync = 1;
inode->i_size = 0;
if (inode->i_blocks)
ext4_truncate(inode);
/*
* Kill off the orphan record which ext4_truncate created.
* AKPM: I think this can be inside the above `if'.
* Note that ext4_orphan_del() has to be able to cope with the
* deletion of a non-existent orphan - this is because we don't
* know if ext4_truncate() actually created an orphan record.
* (Well, we could do this if we need to, but heck - it works)
*/
ext4_orphan_del(handle, inode);
EXT4_I(inode)->i_dtime = get_seconds();
/*
* One subtle ordering requirement: if anything has gone wrong
* (transaction abort, IO errors, whatever), then we can still
* do these next steps (the fs will already have been marked as
* having errors), but we can't free the inode if the mark_dirty
* fails.
*/
if (ext4_mark_inode_dirty(handle, inode))
/* If that failed, just do the required in-core inode clear. */
clear_inode(inode);
else
ext4_free_inode(handle, inode);
ext4_journal_stop(handle);
return;
no_delete:
clear_inode(inode); /* We must guarantee clearing of inode... */
}
typedef struct {
__le32 *p;
__le32 key;
struct buffer_head *bh;
} Indirect;
static inline void add_chain(Indirect *p, struct buffer_head *bh, __le32 *v)
{
p->key = *(p->p = v);
p->bh = bh;
}
/**
* ext4_block_to_path - parse the block number into array of offsets
* @inode: inode in question (we are only interested in its superblock)
* @i_block: block number to be parsed
* @offsets: array to store the offsets in
* @boundary: set this non-zero if the referred-to block is likely to be
* followed (on disk) by an indirect block.
*
* To store the locations of file's data ext4 uses a data structure common
* for UNIX filesystems - tree of pointers anchored in the inode, with
* data blocks at leaves and indirect blocks in intermediate nodes.
* This function translates the block number into path in that tree -
* return value is the path length and @offsets[n] is the offset of
* pointer to (n+1)th node in the nth one. If @block is out of range
* (negative or too large) warning is printed and zero returned.
*
* Note: function doesn't find node addresses, so no IO is needed. All
* we need to know is the capacity of indirect blocks (taken from the
* inode->i_sb).
*/
/*
* Portability note: the last comparison (check that we fit into triple
* indirect block) is spelled differently, because otherwise on an
* architecture with 32-bit longs and 8Kb pages we might get into trouble
* if our filesystem had 8Kb blocks. We might use long long, but that would
* kill us on x86. Oh, well, at least the sign propagation does not matter -
* i_block would have to be negative in the very beginning, so we would not
* get there at all.
*/
static int ext4_block_to_path(struct inode *inode,
ext4_lblk_t i_block,
ext4_lblk_t offsets[4], int *boundary)
{
int ptrs = EXT4_ADDR_PER_BLOCK(inode->i_sb);
int ptrs_bits = EXT4_ADDR_PER_BLOCK_BITS(inode->i_sb);
const long direct_blocks = EXT4_NDIR_BLOCKS,
indirect_blocks = ptrs,
double_blocks = (1 << (ptrs_bits * 2));
int n = 0;
int final = 0;
if (i_block < 0) {
ext4_warning (inode->i_sb, "ext4_block_to_path", "block < 0");
} else if (i_block < direct_blocks) {
offsets[n++] = i_block;
final = direct_blocks;
} else if ( (i_block -= direct_blocks) < indirect_blocks) {
offsets[n++] = EXT4_IND_BLOCK;
offsets[n++] = i_block;
final = ptrs;
} else if ((i_block -= indirect_blocks) < double_blocks) {
offsets[n++] = EXT4_DIND_BLOCK;
offsets[n++] = i_block >> ptrs_bits;
offsets[n++] = i_block & (ptrs - 1);
final = ptrs;
} else if (((i_block -= double_blocks) >> (ptrs_bits * 2)) < ptrs) {
offsets[n++] = EXT4_TIND_BLOCK;
offsets[n++] = i_block >> (ptrs_bits * 2);
offsets[n++] = (i_block >> ptrs_bits) & (ptrs - 1);
offsets[n++] = i_block & (ptrs - 1);
final = ptrs;
} else {
ext4_warning(inode->i_sb, "ext4_block_to_path",
"block %lu > max",
i_block + direct_blocks +
indirect_blocks + double_blocks);
}
if (boundary)
*boundary = final - 1 - (i_block & (ptrs - 1));
return n;
}
/**
* ext4_get_branch - read the chain of indirect blocks leading to data
* @inode: inode in question
* @depth: depth of the chain (1 - direct pointer, etc.)
* @offsets: offsets of pointers in inode/indirect blocks
* @chain: place to store the result
* @err: here we store the error value
*
* Function fills the array of triples <key, p, bh> and returns %NULL
* if everything went OK or the pointer to the last filled triple
* (incomplete one) otherwise. Upon the return chain[i].key contains
* the number of (i+1)-th block in the chain (as it is stored in memory,
* i.e. little-endian 32-bit), chain[i].p contains the address of that
* number (it points into struct inode for i==0 and into the bh->b_data
* for i>0) and chain[i].bh points to the buffer_head of i-th indirect
* block for i>0 and NULL for i==0. In other words, it holds the block
* numbers of the chain, addresses they were taken from (and where we can
* verify that chain did not change) and buffer_heads hosting these
* numbers.
*
* Function stops when it stumbles upon zero pointer (absent block)
* (pointer to last triple returned, *@err == 0)
* or when it gets an IO error reading an indirect block
* (ditto, *@err == -EIO)
* or when it reads all @depth-1 indirect blocks successfully and finds
* the whole chain, all way to the data (returns %NULL, *err == 0).
*
* Need to be called with
* down_read(&EXT4_I(inode)->i_data_sem)
*/
static Indirect *ext4_get_branch(struct inode *inode, int depth,
ext4_lblk_t *offsets,
Indirect chain[4], int *err)
{
struct super_block *sb = inode->i_sb;
Indirect *p = chain;
struct buffer_head *bh;
*err = 0;
/* i_data is not going away, no lock needed */
add_chain (chain, NULL, EXT4_I(inode)->i_data + *offsets);
if (!p->key)
goto no_block;
while (--depth) {
bh = sb_bread(sb, le32_to_cpu(p->key));
if (!bh)
goto failure;
add_chain(++p, bh, (__le32*)bh->b_data + *++offsets);
/* Reader: end */
if (!p->key)
goto no_block;
}
return NULL;
failure:
*err = -EIO;
no_block:
return p;
}
/**
* ext4_find_near - find a place for allocation with sufficient locality
* @inode: owner
* @ind: descriptor of indirect block.
*
* This function returns the preferred place for block allocation.
* It is used when heuristic for sequential allocation fails.
* Rules are:
* + if there is a block to the left of our position - allocate near it.
* + if pointer will live in indirect block - allocate near that block.
* + if pointer will live in inode - allocate in the same
* cylinder group.
*
* In the latter case we colour the starting block by the callers PID to
* prevent it from clashing with concurrent allocations for a different inode
* in the same block group. The PID is used here so that functionally related
* files will be close-by on-disk.
*
* Caller must make sure that @ind is valid and will stay that way.
*/
static ext4_fsblk_t ext4_find_near(struct inode *inode, Indirect *ind)
{
struct ext4_inode_info *ei = EXT4_I(inode);
__le32 *start = ind->bh ? (__le32*) ind->bh->b_data : ei->i_data;
__le32 *p;
ext4_fsblk_t bg_start;
ext4_fsblk_t last_block;
ext4_grpblk_t colour;
/* Try to find previous block */
for (p = ind->p - 1; p >= start; p--) {
if (*p)
return le32_to_cpu(*p);
}
/* No such thing, so let's try location of indirect block */
if (ind->bh)
return ind->bh->b_blocknr;
/*
* It is going to be referred to from the inode itself? OK, just put it
* into the same cylinder group then.
*/
bg_start = ext4_group_first_block_no(inode->i_sb, ei->i_block_group);
last_block = ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es) - 1;
if (bg_start + EXT4_BLOCKS_PER_GROUP(inode->i_sb) <= last_block)
colour = (current->pid % 16) *
(EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16);
else
colour = (current->pid % 16) * ((last_block - bg_start) / 16);
return bg_start + colour;
}
/**
* ext4_find_goal - find a preferred place for allocation.
* @inode: owner
* @block: block we want
* @partial: pointer to the last triple within a chain
*
* Normally this function find the preferred place for block allocation,
* returns it.
*/
static ext4_fsblk_t ext4_find_goal(struct inode *inode, ext4_lblk_t block,
Indirect *partial)
{
struct ext4_block_alloc_info *block_i;
block_i = EXT4_I(inode)->i_block_alloc_info;
/*
* try the heuristic for sequential allocation,
* failing that at least try to get decent locality.
*/
if (block_i && (block == block_i->last_alloc_logical_block + 1)
&& (block_i->last_alloc_physical_block != 0)) {
return block_i->last_alloc_physical_block + 1;
}
return ext4_find_near(inode, partial);
}
/**
* ext4_blks_to_allocate: Look up the block map and count the number
* of direct blocks need to be allocated for the given branch.
*
* @branch: chain of indirect blocks
* @k: number of blocks need for indirect blocks
* @blks: number of data blocks to be mapped.
* @blocks_to_boundary: the offset in the indirect block
*
* return the total number of blocks to be allocate, including the
* direct and indirect blocks.
*/
static int ext4_blks_to_allocate(Indirect *branch, int k, unsigned long blks,
int blocks_to_boundary)
{
unsigned long count = 0;
/*
* Simple case, [t,d]Indirect block(s) has not allocated yet
* then it's clear blocks on that path have not allocated
*/
if (k > 0) {
/* right now we don't handle cross boundary allocation */
if (blks < blocks_to_boundary + 1)
count += blks;
else
count += blocks_to_boundary + 1;
return count;
}
count++;
while (count < blks && count <= blocks_to_boundary &&
le32_to_cpu(*(branch[0].p + count)) == 0) {
count++;
}
return count;
}
/**
* ext4_alloc_blocks: multiple allocate blocks needed for a branch
* @indirect_blks: the number of blocks need to allocate for indirect
* blocks
*
* @new_blocks: on return it will store the new block numbers for
* the indirect blocks(if needed) and the first direct block,
* @blks: on return it will store the total number of allocated
* direct blocks
*/
static int ext4_alloc_blocks(handle_t *handle, struct inode *inode,
ext4_fsblk_t goal, int indirect_blks, int blks,
ext4_fsblk_t new_blocks[4], int *err)
{
int target, i;
unsigned long count = 0;
int index = 0;
ext4_fsblk_t current_block = 0;
int ret = 0;
/*
* Here we try to allocate the requested multiple blocks at once,
* on a best-effort basis.
* To build a branch, we should allocate blocks for
* the indirect blocks(if not allocated yet), and at least
* the first direct block of this branch. That's the
* minimum number of blocks need to allocate(required)
*/
target = blks + indirect_blks;
while (1) {
count = target;
/* allocating blocks for indirect blocks and direct blocks */
current_block = ext4_new_blocks(handle,inode,goal,&count,err);
if (*err)
goto failed_out;
target -= count;
/* allocate blocks for indirect blocks */
while (index < indirect_blks && count) {
new_blocks[index++] = current_block++;
count--;
}
if (count > 0)
break;
}
/* save the new block number for the first direct block */
new_blocks[index] = current_block;
/* total number of blocks allocated for direct blocks */
ret = count;
*err = 0;
return ret;
failed_out:
for (i = 0; i <index; i++)
ext4_free_blocks(handle, inode, new_blocks[i], 1, 0);
return ret;
}
/**
* ext4_alloc_branch - allocate and set up a chain of blocks.
* @inode: owner
* @indirect_blks: number of allocated indirect blocks
* @blks: number of allocated direct blocks
* @offsets: offsets (in the blocks) to store the pointers to next.
* @branch: place to store the chain in.
*
* This function allocates blocks, zeroes out all but the last one,
* links them into chain and (if we are synchronous) writes them to disk.
* In other words, it prepares a branch that can be spliced onto the
* inode. It stores the information about that chain in the branch[], in
* the same format as ext4_get_branch() would do. We are calling it after
* we had read the existing part of chain and partial points to the last
* triple of that (one with zero ->key). Upon the exit we have the same
* picture as after the successful ext4_get_block(), except that in one
* place chain is disconnected - *branch->p is still zero (we did not
* set the last link), but branch->key contains the number that should
* be placed into *branch->p to fill that gap.
*
* If allocation fails we free all blocks we've allocated (and forget
* their buffer_heads) and return the error value the from failed
* ext4_alloc_block() (normally -ENOSPC). Otherwise we set the chain
* as described above and return 0.
*/
static int ext4_alloc_branch(handle_t *handle, struct inode *inode,
int indirect_blks, int *blks, ext4_fsblk_t goal,
ext4_lblk_t *offsets, Indirect *branch)
{
int blocksize = inode->i_sb->s_blocksize;
int i, n = 0;
int err = 0;
struct buffer_head *bh;
int num;
ext4_fsblk_t new_blocks[4];
ext4_fsblk_t current_block;
num = ext4_alloc_blocks(handle, inode, goal, indirect_blks,
*blks, new_blocks, &err);
if (err)
return err;
branch[0].key = cpu_to_le32(new_blocks[0]);
/*
* metadata blocks and data blocks are allocated.
*/
for (n = 1; n <= indirect_blks; n++) {
/*
* Get buffer_head for parent block, zero it out
* and set the pointer to new one, then send
* parent to disk.
*/
bh = sb_getblk(inode->i_sb, new_blocks[n-1]);
branch[n].bh = bh;
lock_buffer(bh);
BUFFER_TRACE(bh, "call get_create_access");
err = ext4_journal_get_create_access(handle, bh);
if (err) {
unlock_buffer(bh);
brelse(bh);
goto failed;
}
memset(bh->b_data, 0, blocksize);
branch[n].p = (__le32 *) bh->b_data + offsets[n];
branch[n].key = cpu_to_le32(new_blocks[n]);
*branch[n].p = branch[n].key;
if ( n == indirect_blks) {
current_block = new_blocks[n];
/*
* End of chain, update the last new metablock of
* the chain to point to the new allocated
* data blocks numbers
*/
for (i=1; i < num; i++)
*(branch[n].p + i) = cpu_to_le32(++current_block);
}
BUFFER_TRACE(bh, "marking uptodate");
set_buffer_uptodate(bh);
unlock_buffer(bh);
BUFFER_TRACE(bh, "call ext4_journal_dirty_metadata");
err = ext4_journal_dirty_metadata(handle, bh);
if (err)
goto failed;
}
*blks = num;
return err;
failed:
/* Allocation failed, free what we already allocated */
for (i = 1; i <= n ; i++) {
BUFFER_TRACE(branch[i].bh, "call jbd2_journal_forget");
ext4_journal_forget(handle, branch[i].bh);
}
for (i = 0; i <indirect_blks; i++)
ext4_free_blocks(handle, inode, new_blocks[i], 1, 0);
ext4_free_blocks(handle, inode, new_blocks[i], num, 0);
return err;
}
/**
* ext4_splice_branch - splice the allocated branch onto inode.
* @inode: owner
* @block: (logical) number of block we are adding
* @chain: chain of indirect blocks (with a missing link - see
* ext4_alloc_branch)
* @where: location of missing link
* @num: number of indirect blocks we are adding
* @blks: number of direct blocks we are adding
*
* This function fills the missing link and does all housekeeping needed in
* inode (->i_blocks, etc.). In case of success we end up with the full
* chain to new block and return 0.
*/
static int ext4_splice_branch(handle_t *handle, struct inode *inode,
ext4_lblk_t block, Indirect *where, int num, int blks)
{
int i;
int err = 0;
struct ext4_block_alloc_info *block_i;
ext4_fsblk_t current_block;
block_i = EXT4_I(inode)->i_block_alloc_info;
/*
* If we're splicing into a [td]indirect block (as opposed to the
* inode) then we need to get write access to the [td]indirect block
* before the splice.
*/
if (where->bh) {
BUFFER_TRACE(where->bh, "get_write_access");
err = ext4_journal_get_write_access(handle, where->bh);
if (err)
goto err_out;
}
/* That's it */
*where->p = where->key;
/*
* Update the host buffer_head or inode to point to more just allocated
* direct blocks blocks
*/
if (num == 0 && blks > 1) {
current_block = le32_to_cpu(where->key) + 1;
for (i = 1; i < blks; i++)
*(where->p + i ) = cpu_to_le32(current_block++);
}
/*
* update the most recently allocated logical & physical block
* in i_block_alloc_info, to assist find the proper goal block for next
* allocation
*/
if (block_i) {
block_i->last_alloc_logical_block = block + blks - 1;
block_i->last_alloc_physical_block =
le32_to_cpu(where[num].key) + blks - 1;
}
/* We are done with atomic stuff, now do the rest of housekeeping */
inode->i_ctime = ext4_current_time(inode);
ext4_mark_inode_dirty(handle, inode);
/* had we spliced it onto indirect block? */
if (where->bh) {
/*
* If we spliced it onto an indirect block, we haven't
* altered the inode. Note however that if it is being spliced
* onto an indirect block at the very end of the file (the
* file is growing) then we *will* alter the inode to reflect
* the new i_size. But that is not done here - it is done in
* generic_commit_write->__mark_inode_dirty->ext4_dirty_inode.
*/
jbd_debug(5, "splicing indirect only\n");
BUFFER_TRACE(where->bh, "call ext4_journal_dirty_metadata");
err = ext4_journal_dirty_metadata(handle, where->bh);
if (err)
goto err_out;
} else {
/*
* OK, we spliced it into the inode itself on a direct block.
* Inode was dirtied above.
*/
jbd_debug(5, "splicing direct\n");
}
return err;
err_out:
for (i = 1; i <= num; i++) {
BUFFER_TRACE(where[i].bh, "call jbd2_journal_forget");
ext4_journal_forget(handle, where[i].bh);
ext4_free_blocks(handle, inode,
le32_to_cpu(where[i-1].key), 1, 0);
}
ext4_free_blocks(handle, inode, le32_to_cpu(where[num].key), blks, 0);
return err;
}
/*
* Allocation strategy is simple: if we have to allocate something, we will
* have to go the whole way to leaf. So let's do it before attaching anything
* to tree, set linkage between the newborn blocks, write them if sync is
* required, recheck the path, free and repeat if check fails, otherwise
* set the last missing link (that will protect us from any truncate-generated
* removals - all blocks on the path are immune now) and possibly force the
* write on the parent block.
* That has a nice additional property: no special recovery from the failed
* allocations is needed - we simply release blocks and do not touch anything
* reachable from inode.
*
* `handle' can be NULL if create == 0.
*
* return > 0, # of blocks mapped or allocated.
* return = 0, if plain lookup failed.
* return < 0, error case.
*
*
* Need to be called with
* down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system block
* (ie, create is zero). Otherwise down_write(&EXT4_I(inode)->i_data_sem)
*/
int ext4_get_blocks_handle(handle_t *handle, struct inode *inode,
ext4_lblk_t iblock, unsigned long maxblocks,
struct buffer_head *bh_result,
int create, int extend_disksize)
{
int err = -EIO;
ext4_lblk_t offsets[4];
Indirect chain[4];
Indirect *partial;
ext4_fsblk_t goal;
int indirect_blks;
int blocks_to_boundary = 0;
int depth;
struct ext4_inode_info *ei = EXT4_I(inode);
int count = 0;
ext4_fsblk_t first_block = 0;
J_ASSERT(!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL));
J_ASSERT(handle != NULL || create == 0);
depth = ext4_block_to_path(inode, iblock, offsets,
&blocks_to_boundary);
if (depth == 0)
goto out;
partial = ext4_get_branch(inode, depth, offsets, chain, &err);
/* Simplest case - block found, no allocation needed */
if (!partial) {
first_block = le32_to_cpu(chain[depth - 1].key);
clear_buffer_new(bh_result);
count++;
/*map more blocks*/
while (count < maxblocks && count <= blocks_to_boundary) {
ext4_fsblk_t blk;
blk = le32_to_cpu(*(chain[depth-1].p + count));
if (blk == first_block + count)
count++;
else
break;
}
goto got_it;
}
/* Next simple case - plain lookup or failed read of indirect block */
if (!create || err == -EIO)
goto cleanup;
/*
* Okay, we need to do block allocation. Lazily initialize the block
* allocation info here if necessary
*/
if (S_ISREG(inode->i_mode) && (!ei->i_block_alloc_info))
ext4_init_block_alloc_info(inode);
goal = ext4_find_goal(inode, iblock, partial);
/* the number of blocks need to allocate for [d,t]indirect blocks */
indirect_blks = (chain + depth) - partial - 1;
/*
* Next look up the indirect map to count the totoal number of
* direct blocks to allocate for this branch.
*/
count = ext4_blks_to_allocate(partial, indirect_blks,
maxblocks, blocks_to_boundary);
/*
* Block out ext4_truncate while we alter the tree
*/
err = ext4_alloc_branch(handle, inode, indirect_blks, &count, goal,
offsets + (partial - chain), partial);
/*
* The ext4_splice_branch call will free and forget any buffers
* on the new chain if there is a failure, but that risks using
* up transaction credits, especially for bitmaps where the
* credits cannot be returned. Can we handle this somehow? We
* may need to return -EAGAIN upwards in the worst case. --sct
*/
if (!err)
err = ext4_splice_branch(handle, inode, iblock,
partial, indirect_blks, count);
/*
* i_disksize growing is protected by i_data_sem. Don't forget to
* protect it if you're about to implement concurrent
* ext4_get_block() -bzzz
*/
if (!err && extend_disksize && inode->i_size > ei->i_disksize)
ei->i_disksize = inode->i_size;
if (err)
goto cleanup;
set_buffer_new(bh_result);
got_it:
map_bh(bh_result, inode->i_sb, le32_to_cpu(chain[depth-1].key));
if (count > blocks_to_boundary)
set_buffer_boundary(bh_result);
err = count;
/* Clean up and exit */
partial = chain + depth - 1; /* the whole chain */
cleanup:
while (partial > chain) {
BUFFER_TRACE(partial->bh, "call brelse");
brelse(partial->bh);
partial--;
}
BUFFER_TRACE(bh_result, "returned");
out:
return err;
}
/* Maximum number of blocks we map for direct IO at once. */
#define DIO_MAX_BLOCKS 4096
/*
* Number of credits we need for writing DIO_MAX_BLOCKS:
* We need sb + group descriptor + bitmap + inode -> 4
* For B blocks with A block pointers per block we need:
* 1 (triple ind.) + (B/A/A + 2) (doubly ind.) + (B/A + 2) (indirect).
* If we plug in 4096 for B and 256 for A (for 1KB block size), we get 25.
*/
#define DIO_CREDITS 25
/*
*
*
* ext4_ext4 get_block() wrapper function
* It will do a look up first, and returns if the blocks already mapped.
* Otherwise it takes the write lock of the i_data_sem and allocate blocks
* and store the allocated blocks in the result buffer head and mark it
* mapped.
*
* If file type is extents based, it will call ext4_ext_get_blocks(),
* Otherwise, call with ext4_get_blocks_handle() to handle indirect mapping
* based files
*
* On success, it returns the number of blocks being mapped or allocate.
* if create==0 and the blocks are pre-allocated and uninitialized block,
* the result buffer head is unmapped. If the create ==1, it will make sure
* the buffer head is mapped.
*
* It returns 0 if plain look up failed (blocks have not been allocated), in
* that casem, buffer head is unmapped
*
* It returns the error in case of allocation failure.
*/
int ext4_get_blocks_wrap(handle_t *handle, struct inode *inode, sector_t block,
unsigned long max_blocks, struct buffer_head *bh,
int create, int extend_disksize)
{
int retval;
clear_buffer_mapped(bh);
/*
* Try to see if we can get the block without requesting
* for new file system block.
*/
down_read((&EXT4_I(inode)->i_data_sem));
if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL) {
retval = ext4_ext_get_blocks(handle, inode, block, max_blocks,
bh, 0, 0);
} else {
retval = ext4_get_blocks_handle(handle,
inode, block, max_blocks, bh, 0, 0);
}
up_read((&EXT4_I(inode)->i_data_sem));
/* If it is only a block(s) look up */
if (!create)
return retval;
/*
* Returns if the blocks have already allocated
*
* Note that if blocks have been preallocated
* ext4_ext_get_block() returns th create = 0
* with buffer head unmapped.
*/
if (retval > 0 && buffer_mapped(bh))
return retval;
/*
* New blocks allocate and/or writing to uninitialized extent
* will possibly result in updating i_data, so we take
* the write lock of i_data_sem, and call get_blocks()
* with create == 1 flag.
*/
down_write((&EXT4_I(inode)->i_data_sem));
/*
* We need to check for EXT4 here because migrate
* could have changed the inode type in between
*/
if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL) {
retval = ext4_ext_get_blocks(handle, inode, block, max_blocks,
bh, create, extend_disksize);
} else {
retval = ext4_get_blocks_handle(handle, inode, block,
max_blocks, bh, create, extend_disksize);
if (retval > 0 && buffer_new(bh)) {
/*
* We allocated new blocks which will result in
* i_data's format changing. Force the migrate
* to fail by clearing migrate flags
*/
EXT4_I(inode)->i_flags = EXT4_I(inode)->i_flags &
~EXT4_EXT_MIGRATE;
}
}
up_write((&EXT4_I(inode)->i_data_sem));
return retval;
}
static int ext4_get_block(struct inode *inode, sector_t iblock,
struct buffer_head *bh_result, int create)
{
handle_t *handle = ext4_journal_current_handle();
int ret = 0, started = 0;
unsigned max_blocks = bh_result->b_size >> inode->i_blkbits;
if (create && !handle) {
/* Direct IO write... */
if (max_blocks > DIO_MAX_BLOCKS)
max_blocks = DIO_MAX_BLOCKS;
handle = ext4_journal_start(inode, DIO_CREDITS +
2 * EXT4_QUOTA_TRANS_BLOCKS(inode->i_sb));
if (IS_ERR(handle)) {
ret = PTR_ERR(handle);
goto out;
}
started = 1;
}
ret = ext4_get_blocks_wrap(handle, inode, iblock,
max_blocks, bh_result, create, 0);
if (ret > 0) {
bh_result->b_size = (ret << inode->i_blkbits);
ret = 0;
}
if (started)
ext4_journal_stop(handle);
out:
return ret;
}
/*
* `handle' can be NULL if create is zero
*/
struct buffer_head *ext4_getblk(handle_t *handle, struct inode *inode,
ext4_lblk_t block, int create, int *errp)
{
struct buffer_head dummy;
int fatal = 0, err;
J_ASSERT(handle != NULL || create == 0);
dummy.b_state = 0;
dummy.b_blocknr = -1000;
buffer_trace_init(&dummy.b_history);
err = ext4_get_blocks_wrap(handle, inode, block, 1,
&dummy, create, 1);
/*
* ext4_get_blocks_handle() returns number of blocks
* mapped. 0 in case of a HOLE.
*/
if (err > 0) {
if (err > 1)
WARN_ON(1);
err = 0;
}
*errp = err;
if (!err && buffer_mapped(&dummy)) {
struct buffer_head *bh;
bh = sb_getblk(inode->i_sb, dummy.b_blocknr);
if (!bh) {
*errp = -EIO;
goto err;
}
if (buffer_new(&dummy)) {
J_ASSERT(create != 0);
J_ASSERT(handle != NULL);
/*
* Now that we do not always journal data, we should
* keep in mind whether this should always journal the
* new buffer as metadata. For now, regular file
* writes use ext4_get_block instead, so it's not a
* problem.
*/
lock_buffer(bh);
BUFFER_TRACE(bh, "call get_create_access");
fatal = ext4_journal_get_create_access(handle, bh);
if (!fatal && !buffer_uptodate(bh)) {
memset(bh->b_data,0,inode->i_sb->s_blocksize);
set_buffer_uptodate(bh);
}
unlock_buffer(bh);
BUFFER_TRACE(bh, "call ext4_journal_dirty_metadata");
err = ext4_journal_dirty_metadata(handle, bh);
if (!fatal)
fatal = err;
} else {
BUFFER_TRACE(bh, "not a new buffer");
}
if (fatal) {
*errp = fatal;
brelse(bh);
bh = NULL;
}
return bh;
}
err:
return NULL;
}
struct buffer_head *ext4_bread(handle_t *handle, struct inode *inode,
ext4_lblk_t block, int create, int *err)
{
struct buffer_head * bh;
bh = ext4_getblk(handle, inode, block, create, err);
if (!bh)
return bh;
if (buffer_uptodate(bh))
return bh;
ll_rw_block(READ_META, 1, &bh);
wait_on_buffer(bh);
if (buffer_uptodate(bh))
return bh;
put_bh(bh);
*err = -EIO;
return NULL;
}
static int walk_page_buffers( handle_t *handle,
struct buffer_head *head,
unsigned from,
unsigned to,
int *partial,
int (*fn)( handle_t *handle,
struct buffer_head *bh))
{
struct buffer_head *bh;
unsigned block_start, block_end;
unsigned blocksize = head->b_size;
int err, ret = 0;
struct buffer_head *next;
for ( bh = head, block_start = 0;
ret == 0 && (bh != head || !block_start);
block_start = block_end, bh = next)
{
next = bh->b_this_page;
block_end = block_start + blocksize;
if (block_end <= from || block_start >= to) {
if (partial && !buffer_uptodate(bh))
*partial = 1;
continue;
}
err = (*fn)(handle, bh);
if (!ret)
ret = err;
}
return ret;
}
/*
* To preserve ordering, it is essential that the hole instantiation and
* the data write be encapsulated in a single transaction. We cannot
* close off a transaction and start a new one between the ext4_get_block()
* and the commit_write(). So doing the jbd2_journal_start at the start of
* prepare_write() is the right place.
*
* Also, this function can nest inside ext4_writepage() ->
* block_write_full_page(). In that case, we *know* that ext4_writepage()
* has generated enough buffer credits to do the whole page. So we won't
* block on the journal in that case, which is good, because the caller may
* be PF_MEMALLOC.
*
* By accident, ext4 can be reentered when a transaction is open via
* quota file writes. If we were to commit the transaction while thus
* reentered, there can be a deadlock - we would be holding a quota
* lock, and the commit would never complete if another thread had a
* transaction open and was blocking on the quota lock - a ranking
* violation.
*
* So what we do is to rely on the fact that jbd2_journal_stop/journal_start
* will _not_ run commit under these circumstances because handle->h_ref
* is elevated. We'll still have enough credits for the tiny quotafile
* write.
*/
static int do_journal_get_write_access(handle_t *handle,
struct buffer_head *bh)
{
if (!buffer_mapped(bh) || buffer_freed(bh))
return 0;
return ext4_journal_get_write_access(handle, bh);
}
static int ext4_write_begin(struct file *file, struct address_space *mapping,
loff_t pos, unsigned len, unsigned flags,
struct page **pagep, void **fsdata)
{
struct inode *inode = mapping->host;
int ret, needed_blocks = ext4_writepage_trans_blocks(inode);
handle_t *handle;
int retries = 0;
struct page *page;
pgoff_t index;
unsigned from, to;
index = pos >> PAGE_CACHE_SHIFT;
from = pos & (PAGE_CACHE_SIZE - 1);
to = from + len;
retry:
page = __grab_cache_page(mapping, index);
if (!page)
return -ENOMEM;
*pagep = page;
handle = ext4_journal_start(inode, needed_blocks);
if (IS_ERR(handle)) {
unlock_page(page);
page_cache_release(page);
ret = PTR_ERR(handle);
goto out;
}
ret = block_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
ext4_get_block);
if (!ret && ext4_should_journal_data(inode)) {
ret = walk_page_buffers(handle, page_buffers(page),
from, to, NULL, do_journal_get_write_access);
}
if (ret) {
ext4_journal_stop(handle);
unlock_page(page);
page_cache_release(page);
}
if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
goto retry;
out:
return ret;
}
int ext4_journal_dirty_data(handle_t *handle, struct buffer_head *bh)
{
int err = jbd2_journal_dirty_data(handle, bh);
if (err)
ext4_journal_abort_handle(__func__, __func__,
bh, handle, err);
return err;
}
/* For write_end() in data=journal mode */
static int write_end_fn(handle_t *handle, struct buffer_head *bh)
{
if (!buffer_mapped(bh) || buffer_freed(bh))
return 0;
set_buffer_uptodate(bh);
return ext4_journal_dirty_metadata(handle, bh);
}
/*
* Generic write_end handler for ordered and writeback ext4 journal modes.
* We can't use generic_write_end, because that unlocks the page and we need to
* unlock the page after ext4_journal_stop, but ext4_journal_stop must run
* after block_write_end.
*/
static int ext4_generic_write_end(struct file *file,
struct address_space *mapping,
loff_t pos, unsigned len, unsigned copied,
struct page *page, void *fsdata)
{
struct inode *inode = file->f_mapping->host;
copied = block_write_end(file, mapping, pos, len, copied, page, fsdata);
if (pos+copied > inode->i_size) {
i_size_write(inode, pos+copied);
mark_inode_dirty(inode);
}
return copied;
}
/*
* We need to pick up the new inode size which generic_commit_write gave us
* `file' can be NULL - eg, when called from page_symlink().
*
* ext4 never places buffers on inode->i_mapping->private_list. metadata
* buffers are managed internally.
*/
static int ext4_ordered_write_end(struct file *file,
struct address_space *mapping,
loff_t pos, unsigned len, unsigned copied,
struct page *page, void *fsdata)
{
handle_t *handle = ext4_journal_current_handle();
struct inode *inode = file->f_mapping->host;
unsigned from, to;
int ret = 0, ret2;
from = pos & (PAGE_CACHE_SIZE - 1);
to = from + len;
ret = walk_page_buffers(handle, page_buffers(page),
from, to, NULL, ext4_journal_dirty_data);
if (ret == 0) {
/*
* generic_write_end() will run mark_inode_dirty() if i_size
* changes. So let's piggyback the i_disksize mark_inode_dirty
* into that.
*/
loff_t new_i_size;
new_i_size = pos + copied;
if (new_i_size > EXT4_I(inode)->i_disksize)
EXT4_I(inode)->i_disksize = new_i_size;
ret2 = ext4_generic_write_end(file, mapping, pos, len, copied,
page, fsdata);
copied = ret2;
if (ret2 < 0)
ret = ret2;
}
ret2 = ext4_journal_stop(handle);
if (!ret)
ret = ret2;
unlock_page(page);
page_cache_release(page);
return ret ? ret : copied;
}
static int ext4_writeback_write_end(struct file *file,
struct address_space *mapping,
loff_t pos, unsigned len, unsigned copied,
struct page *page, void *fsdata)
{
handle_t *handle = ext4_journal_current_handle();
struct inode *inode = file->f_mapping->host;
int ret = 0, ret2;
loff_t new_i_size;
new_i_size = pos + copied;
if (new_i_size > EXT4_I(inode)->i_disksize)
EXT4_I(inode)->i_disksize = new_i_size;
ret2 = ext4_generic_write_end(file, mapping, pos, len, copied,
page, fsdata);
copied = ret2;
if (ret2 < 0)
ret = ret2;
ret2 = ext4_journal_stop(handle);
if (!ret)
ret = ret2;
unlock_page(page);
page_cache_release(page);
return ret ? ret : copied;
}
static int ext4_journalled_write_end(struct file *file,
struct address_space *mapping,
loff_t pos, unsigned len, unsigned copied,
struct page *page, void *fsdata)
{
handle_t *handle = ext4_journal_current_handle();
struct inode *inode = mapping->host;
int ret = 0, ret2;
int partial = 0;
unsigned from, to;
from = pos & (PAGE_CACHE_SIZE - 1);
to = from + len;
if (copied < len) {
if (!PageUptodate(page))
copied = 0;
page_zero_new_buffers(page, from+copied, to);
}
ret = walk_page_buffers(handle, page_buffers(page), from,
to, &partial, write_end_fn);
if (!partial)
SetPageUptodate(page);
if (pos+copied > inode->i_size)
i_size_write(inode, pos+copied);
EXT4_I(inode)->i_state |= EXT4_STATE_JDATA;
if (inode->i_size > EXT4_I(inode)->i_disksize) {
EXT4_I(inode)->i_disksize = inode->i_size;
ret2 = ext4_mark_inode_dirty(handle, inode);
if (!ret)
ret = ret2;
}
ret2 = ext4_journal_stop(handle);
if (!ret)
ret = ret2;
unlock_page(page);
page_cache_release(page);
return ret ? ret : copied;
}
/*
* bmap() is special. It gets used by applications such as lilo and by
* the swapper to find the on-disk block of a specific piece of data.
*
* Naturally, this is dangerous if the block concerned is still in the
* journal. If somebody makes a swapfile on an ext4 data-journaling
* filesystem and enables swap, then they may get a nasty shock when the
* data getting swapped to that swapfile suddenly gets overwritten by
* the original zero's written out previously to the journal and
* awaiting writeback in the kernel's buffer cache.
*
* So, if we see any bmap calls here on a modified, data-journaled file,
* take extra steps to flush any blocks which might be in the cache.
*/
static sector_t ext4_bmap(struct address_space *mapping, sector_t block)
{
struct inode *inode = mapping->host;
journal_t *journal;
int err;
if (EXT4_I(inode)->i_state & EXT4_STATE_JDATA) {
/*
* This is a REALLY heavyweight approach, but the use of
* bmap on dirty files is expected to be extremely rare:
* only if we run lilo or swapon on a freshly made file
* do we expect this to happen.
*
* (bmap requires CAP_SYS_RAWIO so this does not
* represent an unprivileged user DOS attack --- we'd be
* in trouble if mortal users could trigger this path at
* will.)
*
* NB. EXT4_STATE_JDATA is not set on files other than
* regular files. If somebody wants to bmap a directory
* or symlink and gets confused because the buffer
* hasn't yet been flushed to disk, they deserve
* everything they get.
*/
EXT4_I(inode)->i_state &= ~EXT4_STATE_JDATA;
journal = EXT4_JOURNAL(inode);
jbd2_journal_lock_updates(journal);
err = jbd2_journal_flush(journal);
jbd2_journal_unlock_updates(journal);
if (err)
return 0;
}
return generic_block_bmap(mapping,block,ext4_get_block);
}
static int bget_one(handle_t *handle, struct buffer_head *bh)
{
get_bh(bh);
return 0;
}
static int bput_one(handle_t *handle, struct buffer_head *bh)
{
put_bh(bh);
return 0;
}
static int jbd2_journal_dirty_data_fn(handle_t *handle, struct buffer_head *bh)
{
if (buffer_mapped(bh))
return ext4_journal_dirty_data(handle, bh);
return 0;
}
/*
* Note that we always start a transaction even if we're not journalling
* data. This is to preserve ordering: any hole instantiation within
* __block_write_full_page -> ext4_get_block() should be journalled
* along with the data so we don't crash and then get metadata which
* refers to old data.
*
* In all journalling modes block_write_full_page() will start the I/O.
*
* Problem:
*
* ext4_writepage() -> kmalloc() -> __alloc_pages() -> page_launder() ->
* ext4_writepage()
*
* Similar for:
*
* ext4_file_write() -> generic_file_write() -> __alloc_pages() -> ...
*
* Same applies to ext4_get_block(). We will deadlock on various things like
* lock_journal and i_data_sem
*
* Setting PF_MEMALLOC here doesn't work - too many internal memory
* allocations fail.
*
* 16May01: If we're reentered then journal_current_handle() will be
* non-zero. We simply *return*.
*
* 1 July 2001: @@@ FIXME:
* In journalled data mode, a data buffer may be metadata against the
* current transaction. But the same file is part of a shared mapping
* and someone does a writepage() on it.
*
* We will move the buffer onto the async_data list, but *after* it has
* been dirtied. So there's a small window where we have dirty data on
* BJ_Metadata.
*
* Note that this only applies to the last partial page in the file. The
* bit which block_write_full_page() uses prepare/commit for. (That's
* broken code anyway: it's wrong for msync()).
*
* It's a rare case: affects the final partial page, for journalled data
* where the file is subject to bith write() and writepage() in the same
* transction. To fix it we'll need a custom block_write_full_page().
* We'll probably need that anyway for journalling writepage() output.
*
* We don't honour synchronous mounts for writepage(). That would be
* disastrous. Any write() or metadata operation will sync the fs for
* us.
*
* AKPM2: if all the page's buffers are mapped to disk and !data=journal,
* we don't need to open a transaction here.
*/
static int ext4_ordered_writepage(struct page *page,
struct writeback_control *wbc)
{
struct inode *inode = page->mapping->host;
struct buffer_head *page_bufs;
handle_t *handle = NULL;
int ret = 0;
int err;
J_ASSERT(PageLocked(page));
/*
* We give up here if we're reentered, because it might be for a
* different filesystem.
*/
if (ext4_journal_current_handle())
goto out_fail;
handle = ext4_journal_start(inode, ext4_writepage_trans_blocks(inode));
if (IS_ERR(handle)) {
ret = PTR_ERR(handle);
goto out_fail;
}
if (!page_has_buffers(page)) {
create_empty_buffers(page, inode->i_sb->s_blocksize,
(1 << BH_Dirty)|(1 << BH_Uptodate));
}
page_bufs = page_buffers(page);
walk_page_buffers(handle, page_bufs, 0,
PAGE_CACHE_SIZE, NULL, bget_one);
ret = block_write_full_page(page, ext4_get_block, wbc);
/*
* The page can become unlocked at any point now, and
* truncate can then come in and change things. So we
* can't touch *page from now on. But *page_bufs is
* safe due to elevated refcount.
*/
/*
* And attach them to the current transaction. But only if
* block_write_full_page() succeeded. Otherwise they are unmapped,
* and generally junk.
*/
if (ret == 0) {
err = walk_page_buffers(handle, page_bufs, 0, PAGE_CACHE_SIZE,
NULL, jbd2_journal_dirty_data_fn);
if (!ret)
ret = err;
}
walk_page_buffers(handle, page_bufs, 0,
PAGE_CACHE_SIZE, NULL, bput_one);
err = ext4_journal_stop(handle);
if (!ret)
ret = err;
return ret;
out_fail:
redirty_page_for_writepage(wbc, page);
unlock_page(page);
return ret;
}
static int ext4_writeback_writepage(struct page *page,
struct writeback_control *wbc)
{
struct inode *inode = page->mapping->host;
handle_t *handle = NULL;
int ret = 0;
int err;
if (ext4_journal_current_handle())
goto out_fail;
handle = ext4_journal_start(inode, ext4_writepage_trans_blocks(inode));
if (IS_ERR(handle)) {
ret = PTR_ERR(handle);
goto out_fail;
}
if (test_opt(inode->i_sb, NOBH) && ext4_should_writeback_data(inode))
ret = nobh_writepage(page, ext4_get_block, wbc);
else
ret = block_write_full_page(page, ext4_get_block, wbc);
err = ext4_journal_stop(handle);
if (!ret)
ret = err;
return ret;
out_fail:
redirty_page_for_writepage(wbc, page);
unlock_page(page);
return ret;
}
static int ext4_journalled_writepage(struct page *page,
struct writeback_control *wbc)
{
struct inode *inode = page->mapping->host;
handle_t *handle = NULL;
int ret = 0;
int err;
if (ext4_journal_current_handle())
goto no_write;
handle = ext4_journal_start(inode, ext4_writepage_trans_blocks(inode));
if (IS_ERR(handle)) {
ret = PTR_ERR(handle);
goto no_write;
}
if (!page_has_buffers(page) || PageChecked(page)) {
/*
* It's mmapped pagecache. Add buffers and journal it. There
* doesn't seem much point in redirtying the page here.
*/
ClearPageChecked(page);
ret = block_prepare_write(page, 0, PAGE_CACHE_SIZE,
ext4_get_block);
if (ret != 0) {
ext4_journal_stop(handle);
goto out_unlock;
}
ret = walk_page_buffers(handle, page_buffers(page), 0,
PAGE_CACHE_SIZE, NULL, do_journal_get_write_access);
err = walk_page_buffers(handle, page_buffers(page), 0,
PAGE_CACHE_SIZE, NULL, write_end_fn);
if (ret == 0)
ret = err;
EXT4_I(inode)->i_state |= EXT4_STATE_JDATA;
unlock_page(page);
} else {
/*
* It may be a page full of checkpoint-mode buffers. We don't
* really know unless we go poke around in the buffer_heads.
* But block_write_full_page will do the right thing.
*/
ret = block_write_full_page(page, ext4_get_block, wbc);
}
err = ext4_journal_stop(handle);
if (!ret)
ret = err;
out:
return ret;
no_write:
redirty_page_for_writepage(wbc, page);
out_unlock:
unlock_page(page);
goto out;
}
static int ext4_readpage(struct file *file, struct page *page)
{
return mpage_readpage(page, ext4_get_block);
}
static int
ext4_readpages(struct file *file, struct address_space *mapping,
struct list_head *pages, unsigned nr_pages)
{
return mpage_readpages(mapping, pages, nr_pages, ext4_get_block);
}
static void ext4_invalidatepage(struct page *page, unsigned long offset)
{
journal_t *journal = EXT4_JOURNAL(page->mapping->host);
/*
* If it's a full truncate we just forget about the pending dirtying
*/
if (offset == 0)
ClearPageChecked(page);
jbd2_journal_invalidatepage(journal, page, offset);
}
static int ext4_releasepage(struct page *page, gfp_t wait)
{
journal_t *journal = EXT4_JOURNAL(page->mapping->host);
WARN_ON(PageChecked(page));
if (!page_has_buffers(page))
return 0;
return jbd2_journal_try_to_free_buffers(journal, page, wait);
}
/*
* If the O_DIRECT write will extend the file then add this inode to the
* orphan list. So recovery will truncate it back to the original size
* if the machine crashes during the write.
*
* If the O_DIRECT write is intantiating holes inside i_size and the machine
* crashes then stale disk data _may_ be exposed inside the file. But current
* VFS code falls back into buffered path in that case so we are safe.
*/
static ssize_t ext4_direct_IO(int rw, struct kiocb *iocb,
const struct iovec *iov, loff_t offset,
unsigned long nr_segs)
{
struct file *file = iocb->ki_filp;
struct inode *inode = file->f_mapping->host;
struct ext4_inode_info *ei = EXT4_I(inode);
handle_t *handle;
ssize_t ret;
int orphan = 0;
size_t count = iov_length(iov, nr_segs);
if (rw == WRITE) {
loff_t final_size = offset + count;
if (final_size > inode->i_size) {
/* Credits for sb + inode write */
handle = ext4_journal_start(inode, 2);
if (IS_ERR(handle)) {
ret = PTR_ERR(handle);
goto out;
}
ret = ext4_orphan_add(handle, inode);
if (ret) {
ext4_journal_stop(handle);
goto out;
}
orphan = 1;
ei->i_disksize = inode->i_size;
ext4_journal_stop(handle);
}
}
ret = blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iov,
offset, nr_segs,
ext4_get_block, NULL);
if (orphan) {
int err;
/* Credits for sb + inode write */
handle = ext4_journal_start(inode, 2);
if (IS_ERR(handle)) {
/* This is really bad luck. We've written the data
* but cannot extend i_size. Bail out and pretend
* the write failed... */
ret = PTR_ERR(handle);
goto out;
}
if (inode->i_nlink)
ext4_orphan_del(handle, inode);
if (ret > 0) {
loff_t end = offset + ret;
if (end > inode->i_size) {
ei->i_disksize = end;
i_size_write(inode, end);
/*
* We're going to return a positive `ret'
* here due to non-zero-length I/O, so there's
* no way of reporting error returns from
* ext4_mark_inode_dirty() to userspace. So
* ignore it.
*/
ext4_mark_inode_dirty(handle, inode);
}
}
err = ext4_journal_stop(handle);
if (ret == 0)
ret = err;
}
out:
return ret;
}
/*
* Pages can be marked dirty completely asynchronously from ext4's journalling
* activity. By filemap_sync_pte(), try_to_unmap_one(), etc. We cannot do
* much here because ->set_page_dirty is called under VFS locks. The page is
* not necessarily locked.
*
* We cannot just dirty the page and leave attached buffers clean, because the
* buffers' dirty state is "definitive". We cannot just set the buffers dirty
* or jbddirty because all the journalling code will explode.
*
* So what we do is to mark the page "pending dirty" and next time writepage
* is called, propagate that into the buffers appropriately.
*/
static int ext4_journalled_set_page_dirty(struct page *page)
{
SetPageChecked(page);
return __set_page_dirty_nobuffers(page);
}
static const struct address_space_operations ext4_ordered_aops = {
.readpage = ext4_readpage,
.readpages = ext4_readpages,
.writepage = ext4_ordered_writepage,
.sync_page = block_sync_page,
.write_begin = ext4_write_begin,
.write_end = ext4_ordered_write_end,
.bmap = ext4_bmap,
.invalidatepage = ext4_invalidatepage,
.releasepage = ext4_releasepage,
.direct_IO = ext4_direct_IO,
.migratepage = buffer_migrate_page,
};
static const struct address_space_operations ext4_writeback_aops = {
.readpage = ext4_readpage,
.readpages = ext4_readpages,
.writepage = ext4_writeback_writepage,
.sync_page = block_sync_page,
.write_begin = ext4_write_begin,
.write_end = ext4_writeback_write_end,
.bmap = ext4_bmap,
.invalidatepage = ext4_invalidatepage,
.releasepage = ext4_releasepage,
.direct_IO = ext4_direct_IO,
.migratepage = buffer_migrate_page,
};
static const struct address_space_operations ext4_journalled_aops = {
.readpage = ext4_readpage,
.readpages = ext4_readpages,
.writepage = ext4_journalled_writepage,
.sync_page = block_sync_page,
.write_begin = ext4_write_begin,
.write_end = ext4_journalled_write_end,
.set_page_dirty = ext4_journalled_set_page_dirty,
.bmap = ext4_bmap,
.invalidatepage = ext4_invalidatepage,
.releasepage = ext4_releasepage,
};
void ext4_set_aops(struct inode *inode)
{
if (ext4_should_order_data(inode))
inode->i_mapping->a_ops = &ext4_ordered_aops;
else if (ext4_should_writeback_data(inode))
inode->i_mapping->a_ops = &ext4_writeback_aops;
else
inode->i_mapping->a_ops = &ext4_journalled_aops;
}
/*
* ext4_block_truncate_page() zeroes out a mapping from file offset `from'
* up to the end of the block which corresponds to `from'.
* This required during truncate. We need to physically zero the tail end
* of that block so it doesn't yield old data if the file is later grown.
*/
int ext4_block_truncate_page(handle_t *handle, struct page *page,
struct address_space *mapping, loff_t from)
{
ext4_fsblk_t index = from >> PAGE_CACHE_SHIFT;
unsigned offset = from & (PAGE_CACHE_SIZE-1);
unsigned blocksize, length, pos;
ext4_lblk_t iblock;
struct inode *inode = mapping->host;
struct buffer_head *bh;
int err = 0;
blocksize = inode->i_sb->s_blocksize;
length = blocksize - (offset & (blocksize - 1));
iblock = index << (PAGE_CACHE_SHIFT - inode->i_sb->s_blocksize_bits);
/*
* For "nobh" option, we can only work if we don't need to
* read-in the page - otherwise we create buffers to do the IO.
*/
if (!page_has_buffers(page) && test_opt(inode->i_sb, NOBH) &&
ext4_should_writeback_data(inode) && PageUptodate(page)) {
zero_user(page, offset, length);
set_page_dirty(page);
goto unlock;
}
if (!page_has_buffers(page))
create_empty_buffers(page, blocksize, 0);
/* Find the buffer that contains "offset" */
bh = page_buffers(page);
pos = blocksize;
while (offset >= pos) {
bh = bh->b_this_page;
iblock++;
pos += blocksize;
}
err = 0;
if (buffer_freed(bh)) {
BUFFER_TRACE(bh, "freed: skip");
goto unlock;
}
if (!buffer_mapped(bh)) {
BUFFER_TRACE(bh, "unmapped");
ext4_get_block(inode, iblock, bh, 0);
/* unmapped? It's a hole - nothing to do */
if (!buffer_mapped(bh)) {
BUFFER_TRACE(bh, "still unmapped");
goto unlock;
}
}
/* Ok, it's mapped. Make sure it's up-to-date */
if (PageUptodate(page))
set_buffer_uptodate(bh);
if (!buffer_uptodate(bh)) {
err = -EIO;
ll_rw_block(READ, 1, &bh);
wait_on_buffer(bh);
/* Uhhuh. Read error. Complain and punt. */
if (!buffer_uptodate(bh))
goto unlock;
}
if (ext4_should_journal_data(inode)) {
BUFFER_TRACE(bh, "get write access");
err = ext4_journal_get_write_access(handle, bh);
if (err)
goto unlock;
}
zero_user(page, offset, length);
BUFFER_TRACE(bh, "zeroed end of block");
err = 0;
if (ext4_should_journal_data(inode)) {
err = ext4_journal_dirty_metadata(handle, bh);
} else {
if (ext4_should_order_data(inode))
err = ext4_journal_dirty_data(handle, bh);
mark_buffer_dirty(bh);
}
unlock:
unlock_page(page);
page_cache_release(page);
return err;
}
/*
* Probably it should be a library function... search for first non-zero word
* or memcmp with zero_page, whatever is better for particular architecture.
* Linus?
*/
static inline int all_zeroes(__le32 *p, __le32 *q)
{
while (p < q)
if (*p++)
return 0;
return 1;
}
/**
* ext4_find_shared - find the indirect blocks for partial truncation.
* @inode: inode in question
* @depth: depth of the affected branch
* @offsets: offsets of pointers in that branch (see ext4_block_to_path)
* @chain: place to store the pointers to partial indirect blocks
* @top: place to the (detached) top of branch
*
* This is a helper function used by ext4_truncate().
*
* When we do truncate() we may have to clean the ends of several
* indirect blocks but leave the blocks themselves alive. Block is
* partially truncated if some data below the new i_size is refered
* from it (and it is on the path to the first completely truncated
* data block, indeed). We have to free the top of that path along
* with everything to the right of the path. Since no allocation
* past the truncation point is possible until ext4_truncate()
* finishes, we may safely do the latter, but top of branch may
* require special attention - pageout below the truncation point
* might try to populate it.
*
* We atomically detach the top of branch from the tree, store the
* block number of its root in *@top, pointers to buffer_heads of
* partially truncated blocks - in @chain[].bh and pointers to
* their last elements that should not be removed - in
* @chain[].p. Return value is the pointer to last filled element
* of @chain.
*
* The work left to caller to do the actual freeing of subtrees:
* a) free the subtree starting from *@top
* b) free the subtrees whose roots are stored in
* (@chain[i].p+1 .. end of @chain[i].bh->b_data)
* c) free the subtrees growing from the inode past the @chain[0].
* (no partially truncated stuff there). */
static Indirect *ext4_find_shared(struct inode *inode, int depth,
ext4_lblk_t offsets[4], Indirect chain[4], __le32 *top)
{
Indirect *partial, *p;
int k, err;
*top = 0;
/* Make k index the deepest non-null offest + 1 */
for (k = depth; k > 1 && !offsets[k-1]; k--)
;
partial = ext4_get_branch(inode, k, offsets, chain, &err);
/* Writer: pointers */
if (!partial)
partial = chain + k-1;
/*
* If the branch acquired continuation since we've looked at it -
* fine, it should all survive and (new) top doesn't belong to us.
*/
if (!partial->key && *partial->p)
/* Writer: end */
goto no_top;
for (p=partial; p>chain && all_zeroes((__le32*)p->bh->b_data,p->p); p--)
;
/*
* OK, we've found the last block that must survive. The rest of our
* branch should be detached before unlocking. However, if that rest
* of branch is all ours and does not grow immediately from the inode
* it's easier to cheat and just decrement partial->p.
*/
if (p == chain + k - 1 && p > chain) {
p->p--;
} else {
*top = *p->p;
/* Nope, don't do this in ext4. Must leave the tree intact */
#if 0
*p->p = 0;
#endif
}
/* Writer: end */
while(partial > p) {
brelse(partial->bh);
partial--;
}
no_top:
return partial;
}
/*
* Zero a number of block pointers in either an inode or an indirect block.
* If we restart the transaction we must again get write access to the
* indirect block for further modification.
*
* We release `count' blocks on disk, but (last - first) may be greater
* than `count' because there can be holes in there.
*/
static void ext4_clear_blocks(handle_t *handle, struct inode *inode,
struct buffer_head *bh, ext4_fsblk_t block_to_free,
unsigned long count, __le32 *first, __le32 *last)
{
__le32 *p;
if (try_to_extend_transaction(handle, inode)) {
if (bh) {
BUFFER_TRACE(bh, "call ext4_journal_dirty_metadata");
ext4_journal_dirty_metadata(handle, bh);
}
ext4_mark_inode_dirty(handle, inode);
ext4_journal_test_restart(handle, inode);
if (bh) {
BUFFER_TRACE(bh, "retaking write access");
ext4_journal_get_write_access(handle, bh);
}
}
/*
* Any buffers which are on the journal will be in memory. We find
* them on the hash table so jbd2_journal_revoke() will run jbd2_journal_forget()
* on them. We've already detached each block from the file, so
* bforget() in jbd2_journal_forget() should be safe.
*
* AKPM: turn on bforget in jbd2_journal_forget()!!!
*/
for (p = first; p < last; p++) {
u32 nr = le32_to_cpu(*p);
if (nr) {
struct buffer_head *tbh;
*p = 0;
tbh = sb_find_get_block(inode->i_sb, nr);
ext4_forget(handle, 0, inode, tbh, nr);
}
}
ext4_free_blocks(handle, inode, block_to_free, count, 0);
}
/**
* ext4_free_data - free a list of data blocks
* @handle: handle for this transaction
* @inode: inode we are dealing with
* @this_bh: indirect buffer_head which contains *@first and *@last
* @first: array of block numbers
* @last: points immediately past the end of array
*
* We are freeing all blocks refered from that array (numbers are stored as
* little-endian 32-bit) and updating @inode->i_blocks appropriately.
*
* We accumulate contiguous runs of blocks to free. Conveniently, if these
* blocks are contiguous then releasing them at one time will only affect one
* or two bitmap blocks (+ group descriptor(s) and superblock) and we won't
* actually use a lot of journal space.
*
* @this_bh will be %NULL if @first and @last point into the inode's direct
* block pointers.
*/
static void ext4_free_data(handle_t *handle, struct inode *inode,
struct buffer_head *this_bh,
__le32 *first, __le32 *last)
{
ext4_fsblk_t block_to_free = 0; /* Starting block # of a run */
unsigned long count = 0; /* Number of blocks in the run */
__le32 *block_to_free_p = NULL; /* Pointer into inode/ind
corresponding to
block_to_free */
ext4_fsblk_t nr; /* Current block # */
__le32 *p; /* Pointer into inode/ind
for current block */
int err;
if (this_bh) { /* For indirect block */
BUFFER_TRACE(this_bh, "get_write_access");
err = ext4_journal_get_write_access(handle, this_bh);
/* Important: if we can't update the indirect pointers
* to the blocks, we can't free them. */
if (err)
return;
}
for (p = first; p < last; p++) {
nr = le32_to_cpu(*p);
if (nr) {
/* accumulate blocks to free if they're contiguous */
if (count == 0) {
block_to_free = nr;
block_to_free_p = p;
count = 1;
} else if (nr == block_to_free + count) {
count++;
} else {
ext4_clear_blocks(handle, inode, this_bh,
block_to_free,
count, block_to_free_p, p);
block_to_free = nr;
block_to_free_p = p;
count = 1;
}
}
}
if (count > 0)
ext4_clear_blocks(handle, inode, this_bh, block_to_free,
count, block_to_free_p, p);
if (this_bh) {
BUFFER_TRACE(this_bh, "call ext4_journal_dirty_metadata");
/*
* The buffer head should have an attached journal head at this
* point. However, if the data is corrupted and an indirect
* block pointed to itself, it would have been detached when
* the block was cleared. Check for this instead of OOPSing.
*/
if (bh2jh(this_bh))
ext4_journal_dirty_metadata(handle, this_bh);
else
ext4_error(inode->i_sb, __func__,
"circular indirect block detected, "
"inode=%lu, block=%llu",
inode->i_ino,
(unsigned long long) this_bh->b_blocknr);
}
}
/**
* ext4_free_branches - free an array of branches
* @handle: JBD handle for this transaction
* @inode: inode we are dealing with
* @parent_bh: the buffer_head which contains *@first and *@last
* @first: array of block numbers
* @last: pointer immediately past the end of array
* @depth: depth of the branches to free
*
* We are freeing all blocks refered from these branches (numbers are
* stored as little-endian 32-bit) and updating @inode->i_blocks
* appropriately.
*/
static void ext4_free_branches(handle_t *handle, struct inode *inode,
struct buffer_head *parent_bh,
__le32 *first, __le32 *last, int depth)
{
ext4_fsblk_t nr;
__le32 *p;
if (is_handle_aborted(handle))
return;
if (depth--) {
struct buffer_head *bh;
int addr_per_block = EXT4_ADDR_PER_BLOCK(inode->i_sb);
p = last;
while (--p >= first) {
nr = le32_to_cpu(*p);
if (!nr)
continue; /* A hole */
/* Go read the buffer for the next level down */
bh = sb_bread(inode->i_sb, nr);
/*
* A read failure? Report error and clear slot
* (should be rare).
*/
if (!bh) {
ext4_error(inode->i_sb, "ext4_free_branches",
"Read failure, inode=%lu, block=%llu",
inode->i_ino, nr);
continue;
}
/* This zaps the entire block. Bottom up. */
BUFFER_TRACE(bh, "free child branches");
ext4_free_branches(handle, inode, bh,
(__le32*)bh->b_data,
(__le32*)bh->b_data + addr_per_block,
depth);
/*
* We've probably journalled the indirect block several
* times during the truncate. But it's no longer
* needed and we now drop it from the transaction via
* jbd2_journal_revoke().
*
* That's easy if it's exclusively part of this
* transaction. But if it's part of the committing
* transaction then jbd2_journal_forget() will simply
* brelse() it. That means that if the underlying
* block is reallocated in ext4_get_block(),
* unmap_underlying_metadata() will find this block
* and will try to get rid of it. damn, damn.
*
* If this block has already been committed to the
* journal, a revoke record will be written. And
* revoke records must be emitted *before* clearing
* this block's bit in the bitmaps.
*/
ext4_forget(handle, 1, inode, bh, bh->b_blocknr);
/*
* Everything below this this pointer has been
* released. Now let this top-of-subtree go.
*
* We want the freeing of this indirect block to be
* atomic in the journal with the updating of the
* bitmap block which owns it. So make some room in
* the journal.
*
* We zero the parent pointer *after* freeing its
* pointee in the bitmaps, so if extend_transaction()
* for some reason fails to put the bitmap changes and
* the release into the same transaction, recovery
* will merely complain about releasing a free block,
* rather than leaking blocks.
*/
if (is_handle_aborted(handle))
return;
if (try_to_extend_transaction(handle, inode)) {
ext4_mark_inode_dirty(handle, inode);
ext4_journal_test_restart(handle, inode);
}
ext4_free_blocks(handle, inode, nr, 1, 1);
if (parent_bh) {
/*
* The block which we have just freed is
* pointed to by an indirect block: journal it
*/
BUFFER_TRACE(parent_bh, "get_write_access");
if (!ext4_journal_get_write_access(handle,
parent_bh)){
*p = 0;
BUFFER_TRACE(parent_bh,
"call ext4_journal_dirty_metadata");
ext4_journal_dirty_metadata(handle,
parent_bh);
}
}
}
} else {
/* We have reached the bottom of the tree. */
BUFFER_TRACE(parent_bh, "free data blocks");
ext4_free_data(handle, inode, parent_bh, first, last);
}
}
int ext4_can_truncate(struct inode *inode)
{
if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
return 0;
if (S_ISREG(inode->i_mode))
return 1;
if (S_ISDIR(inode->i_mode))
return 1;
if (S_ISLNK(inode->i_mode))
return !ext4_inode_is_fast_symlink(inode);
return 0;
}
/*
* ext4_truncate()
*
* We block out ext4_get_block() block instantiations across the entire
* transaction, and VFS/VM ensures that ext4_truncate() cannot run
* simultaneously on behalf of the same inode.
*
* As we work through the truncate and commmit bits of it to the journal there
* is one core, guiding principle: the file's tree must always be consistent on
* disk. We must be able to restart the truncate after a crash.
*
* The file's tree may be transiently inconsistent in memory (although it
* probably isn't), but whenever we close off and commit a journal transaction,
* the contents of (the filesystem + the journal) must be consistent and
* restartable. It's pretty simple, really: bottom up, right to left (although
* left-to-right works OK too).
*
* Note that at recovery time, journal replay occurs *before* the restart of
* truncate against the orphan inode list.
*
* The committed inode has the new, desired i_size (which is the same as
* i_disksize in this case). After a crash, ext4_orphan_cleanup() will see
* that this inode's truncate did not complete and it will again call
* ext4_truncate() to have another go. So there will be instantiated blocks
* to the right of the truncation point in a crashed ext4 filesystem. But
* that's fine - as long as they are linked from the inode, the post-crash
* ext4_truncate() run will find them and release them.
*/
void ext4_truncate(struct inode *inode)
{
handle_t *handle;
struct ext4_inode_info *ei = EXT4_I(inode);
__le32 *i_data = ei->i_data;
int addr_per_block = EXT4_ADDR_PER_BLOCK(inode->i_sb);
struct address_space *mapping = inode->i_mapping;
ext4_lblk_t offsets[4];
Indirect chain[4];
Indirect *partial;
__le32 nr = 0;
int n;
ext4_lblk_t last_block;
unsigned blocksize = inode->i_sb->s_blocksize;
struct page *page;
if (!ext4_can_truncate(inode))
return;
/*
* We have to lock the EOF page here, because lock_page() nests
* outside jbd2_journal_start().
*/
if ((inode->i_size & (blocksize - 1)) == 0) {
/* Block boundary? Nothing to do */
page = NULL;
} else {
page = grab_cache_page(mapping,
inode->i_size >> PAGE_CACHE_SHIFT);
if (!page)
return;
}
if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL) {
ext4_ext_truncate(inode, page);
return;
}
handle = start_transaction(inode);
if (IS_ERR(handle)) {
if (page) {
clear_highpage(page);
flush_dcache_page(page);
unlock_page(page);
page_cache_release(page);
}
return; /* AKPM: return what? */
}
last_block = (inode->i_size + blocksize-1)
>> EXT4_BLOCK_SIZE_BITS(inode->i_sb);
if (page)
ext4_block_truncate_page(handle, page, mapping, inode->i_size);
n = ext4_block_to_path(inode, last_block, offsets, NULL);
if (n == 0)
goto out_stop; /* error */
/*
* OK. This truncate is going to happen. We add the inode to the
* orphan list, so that if this truncate spans multiple transactions,
* and we crash, we will resume the truncate when the filesystem
* recovers. It also marks the inode dirty, to catch the new size.
*
* Implication: the file must always be in a sane, consistent
* truncatable state while each transaction commits.
*/
if (ext4_orphan_add(handle, inode))
goto out_stop;
/*
* The orphan list entry will now protect us from any crash which
* occurs before the truncate completes, so it is now safe to propagate
* the new, shorter inode size (held for now in i_size) into the
* on-disk inode. We do this via i_disksize, which is the value which
* ext4 *really* writes onto the disk inode.
*/
ei->i_disksize = inode->i_size;
/*
* From here we block out all ext4_get_block() callers who want to
* modify the block allocation tree.
*/
down_write(&ei->i_data_sem);
if (n == 1) { /* direct blocks */
ext4_free_data(handle, inode, NULL, i_data+offsets[0],
i_data + EXT4_NDIR_BLOCKS);
goto do_indirects;
}
partial = ext4_find_shared(inode, n, offsets, chain, &nr);
/* Kill the top of shared branch (not detached) */
if (nr) {
if (partial == chain) {
/* Shared branch grows from the inode */
ext4_free_branches(handle, inode, NULL,
&nr, &nr+1, (chain+n-1) - partial);
*partial->p = 0;
/*
* We mark the inode dirty prior to restart,
* and prior to stop. No need for it here.
*/
} else {
/* Shared branch grows from an indirect block */
BUFFER_TRACE(partial->bh, "get_write_access");
ext4_free_branches(handle, inode, partial->bh,
partial->p,
partial->p+1, (chain+n-1) - partial);
}
}
/* Clear the ends of indirect blocks on the shared branch */
while (partial > chain) {
ext4_free_branches(handle, inode, partial->bh, partial->p + 1,
(__le32*)partial->bh->b_data+addr_per_block,
(chain+n-1) - partial);
BUFFER_TRACE(partial->bh, "call brelse");
brelse (partial->bh);
partial--;
}
do_indirects:
/* Kill the remaining (whole) subtrees */
switch (offsets[0]) {
default:
nr = i_data[EXT4_IND_BLOCK];
if (nr) {
ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 1);
i_data[EXT4_IND_BLOCK] = 0;
}
case EXT4_IND_BLOCK:
nr = i_data[EXT4_DIND_BLOCK];
if (nr) {
ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 2);
i_data[EXT4_DIND_BLOCK] = 0;
}
case EXT4_DIND_BLOCK:
nr = i_data[EXT4_TIND_BLOCK];
if (nr) {
ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 3);
i_data[EXT4_TIND_BLOCK] = 0;
}
case EXT4_TIND_BLOCK:
;
}
ext4_discard_reservation(inode);
up_write(&ei->i_data_sem);
inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
ext4_mark_inode_dirty(handle, inode);
/*
* In a multi-transaction truncate, we only make the final transaction
* synchronous
*/
if (IS_SYNC(inode))
handle->h_sync = 1;
out_stop:
/*
* If this was a simple ftruncate(), and the file will remain alive
* then we need to clear up the orphan record which we created above.
* However, if this was a real unlink then we were called by
* ext4_delete_inode(), and we allow that function to clean up the
* orphan info for us.
*/
if (inode->i_nlink)
ext4_orphan_del(handle, inode);
ext4_journal_stop(handle);
}
static ext4_fsblk_t ext4_get_inode_block(struct super_block *sb,
unsigned long ino, struct ext4_iloc *iloc)
{
ext4_group_t block_group;
unsigned long offset;
ext4_fsblk_t block;
struct ext4_group_desc *gdp;
if (!ext4_valid_inum(sb, ino)) {
/*
* This error is already checked for in namei.c unless we are
* looking at an NFS filehandle, in which case no error
* report is needed
*/
return 0;
}
block_group = (ino - 1) / EXT4_INODES_PER_GROUP(sb);
gdp = ext4_get_group_desc(sb, block_group, NULL);
if (!gdp)
return 0;
/*
* Figure out the offset within the block group inode table
*/
offset = ((ino - 1) % EXT4_INODES_PER_GROUP(sb)) *
EXT4_INODE_SIZE(sb);
block = ext4_inode_table(sb, gdp) +
(offset >> EXT4_BLOCK_SIZE_BITS(sb));
iloc->block_group = block_group;
iloc->offset = offset & (EXT4_BLOCK_SIZE(sb) - 1);
return block;
}
/*
* ext4_get_inode_loc returns with an extra refcount against the inode's
* underlying buffer_head on success. If 'in_mem' is true, we have all
* data in memory that is needed to recreate the on-disk version of this
* inode.
*/
static int __ext4_get_inode_loc(struct inode *inode,
struct ext4_iloc *iloc, int in_mem)
{
ext4_fsblk_t block;
struct buffer_head *bh;
block = ext4_get_inode_block(inode->i_sb, inode->i_ino, iloc);
if (!block)
return -EIO;
bh = sb_getblk(inode->i_sb, block);
if (!bh) {
ext4_error (inode->i_sb, "ext4_get_inode_loc",
"unable to read inode block - "
"inode=%lu, block=%llu",
inode->i_ino, block);
return -EIO;
}
if (!buffer_uptodate(bh)) {
lock_buffer(bh);
if (buffer_uptodate(bh)) {
/* someone brought it uptodate while we waited */
unlock_buffer(bh);
goto has_buffer;
}
/*
* If we have all information of the inode in memory and this
* is the only valid inode in the block, we need not read the
* block.
*/
if (in_mem) {
struct buffer_head *bitmap_bh;
struct ext4_group_desc *desc;
int inodes_per_buffer;
int inode_offset, i;
ext4_group_t block_group;
int start;
block_group = (inode->i_ino - 1) /
EXT4_INODES_PER_GROUP(inode->i_sb);
inodes_per_buffer = bh->b_size /
EXT4_INODE_SIZE(inode->i_sb);
inode_offset = ((inode->i_ino - 1) %
EXT4_INODES_PER_GROUP(inode->i_sb));
start = inode_offset & ~(inodes_per_buffer - 1);
/* Is the inode bitmap in cache? */
desc = ext4_get_group_desc(inode->i_sb,
block_group, NULL);
if (!desc)
goto make_io;
bitmap_bh = sb_getblk(inode->i_sb,
ext4_inode_bitmap(inode->i_sb, desc));
if (!bitmap_bh)
goto make_io;
/*
* If the inode bitmap isn't in cache then the
* optimisation may end up performing two reads instead
* of one, so skip it.
*/
if (!buffer_uptodate(bitmap_bh)) {
brelse(bitmap_bh);
goto make_io;
}
for (i = start; i < start + inodes_per_buffer; i++) {
if (i == inode_offset)
continue;
if (ext4_test_bit(i, bitmap_bh->b_data))
break;
}
brelse(bitmap_bh);
if (i == start + inodes_per_buffer) {
/* all other inodes are free, so skip I/O */
memset(bh->b_data, 0, bh->b_size);
set_buffer_uptodate(bh);
unlock_buffer(bh);
goto has_buffer;
}
}
make_io:
/*
* There are other valid inodes in the buffer, this inode
* has in-inode xattrs, or we don't have this inode in memory.
* Read the block from disk.
*/
get_bh(bh);
bh->b_end_io = end_buffer_read_sync;
submit_bh(READ_META, bh);
wait_on_buffer(bh);
if (!buffer_uptodate(bh)) {
ext4_error(inode->i_sb, "ext4_get_inode_loc",
"unable to read inode block - "
"inode=%lu, block=%llu",
inode->i_ino, block);
brelse(bh);
return -EIO;
}
}
has_buffer:
iloc->bh = bh;
return 0;
}
int ext4_get_inode_loc(struct inode *inode, struct ext4_iloc *iloc)
{
/* We have all inode data except xattrs in memory here. */
return __ext4_get_inode_loc(inode, iloc,
!(EXT4_I(inode)->i_state & EXT4_STATE_XATTR));
}
void ext4_set_inode_flags(struct inode *inode)
{
unsigned int flags = EXT4_I(inode)->i_flags;
inode->i_flags &= ~(S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC);
if (flags & EXT4_SYNC_FL)
inode->i_flags |= S_SYNC;
if (flags & EXT4_APPEND_FL)
inode->i_flags |= S_APPEND;
if (flags & EXT4_IMMUTABLE_FL)
inode->i_flags |= S_IMMUTABLE;
if (flags & EXT4_NOATIME_FL)
inode->i_flags |= S_NOATIME;
if (flags & EXT4_DIRSYNC_FL)
inode->i_flags |= S_DIRSYNC;
}
/* Propagate flags from i_flags to EXT4_I(inode)->i_flags */
void ext4_get_inode_flags(struct ext4_inode_info *ei)
{
unsigned int flags = ei->vfs_inode.i_flags;
ei->i_flags &= ~(EXT4_SYNC_FL|EXT4_APPEND_FL|
EXT4_IMMUTABLE_FL|EXT4_NOATIME_FL|EXT4_DIRSYNC_FL);
if (flags & S_SYNC)
ei->i_flags |= EXT4_SYNC_FL;
if (flags & S_APPEND)
ei->i_flags |= EXT4_APPEND_FL;
if (flags & S_IMMUTABLE)
ei->i_flags |= EXT4_IMMUTABLE_FL;
if (flags & S_NOATIME)
ei->i_flags |= EXT4_NOATIME_FL;
if (flags & S_DIRSYNC)
ei->i_flags |= EXT4_DIRSYNC_FL;
}
static blkcnt_t ext4_inode_blocks(struct ext4_inode *raw_inode,
struct ext4_inode_info *ei)
{
blkcnt_t i_blocks ;
struct inode *inode = &(ei->vfs_inode);
struct super_block *sb = inode->i_sb;
if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
EXT4_FEATURE_RO_COMPAT_HUGE_FILE)) {
/* we are using combined 48 bit field */
i_blocks = ((u64)le16_to_cpu(raw_inode->i_blocks_high)) << 32 |
le32_to_cpu(raw_inode->i_blocks_lo);
if (ei->i_flags & EXT4_HUGE_FILE_FL) {
/* i_blocks represent file system block size */
return i_blocks << (inode->i_blkbits - 9);
} else {
return i_blocks;
}
} else {
return le32_to_cpu(raw_inode->i_blocks_lo);
}
}
struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
{
struct ext4_iloc iloc;
struct ext4_inode *raw_inode;
struct ext4_inode_info *ei;
struct buffer_head *bh;
struct inode *inode;
long ret;
int block;
inode = iget_locked(sb, ino);
if (!inode)
return ERR_PTR(-ENOMEM);
if (!(inode->i_state & I_NEW))
return inode;
ei = EXT4_I(inode);
#ifdef CONFIG_EXT4DEV_FS_POSIX_ACL
ei->i_acl = EXT4_ACL_NOT_CACHED;
ei->i_default_acl = EXT4_ACL_NOT_CACHED;
#endif
ei->i_block_alloc_info = NULL;
ret = __ext4_get_inode_loc(inode, &iloc, 0);
if (ret < 0)
goto bad_inode;
bh = iloc.bh;
raw_inode = ext4_raw_inode(&iloc);
inode->i_mode = le16_to_cpu(raw_inode->i_mode);
inode->i_uid = (uid_t)le16_to_cpu(raw_inode->i_uid_low);
inode->i_gid = (gid_t)le16_to_cpu(raw_inode->i_gid_low);
if(!(test_opt (inode->i_sb, NO_UID32))) {
inode->i_uid |= le16_to_cpu(raw_inode->i_uid_high) << 16;
inode->i_gid |= le16_to_cpu(raw_inode->i_gid_high) << 16;
}
inode->i_nlink = le16_to_cpu(raw_inode->i_links_count);
ei->i_state = 0;
ei->i_dir_start_lookup = 0;
ei->i_dtime = le32_to_cpu(raw_inode->i_dtime);
/* We now have enough fields to check if the inode was active or not.
* This is needed because nfsd might try to access dead inodes
* the test is that same one that e2fsck uses
* NeilBrown 1999oct15
*/
if (inode->i_nlink == 0) {
if (inode->i_mode == 0 ||
!(EXT4_SB(inode->i_sb)->s_mount_state & EXT4_ORPHAN_FS)) {
/* this inode is deleted */
brelse (bh);
ret = -ESTALE;
goto bad_inode;
}
/* The only unlinked inodes we let through here have
* valid i_mode and are being read by the orphan
* recovery code: that's fine, we're about to complete
* the process of deleting those. */
}
ei->i_flags = le32_to_cpu(raw_inode->i_flags);
inode->i_blocks = ext4_inode_blocks(raw_inode, ei);
ei->i_file_acl = le32_to_cpu(raw_inode->i_file_acl_lo);
if (EXT4_SB(inode->i_sb)->s_es->s_creator_os !=
cpu_to_le32(EXT4_OS_HURD)) {
ei->i_file_acl |=
((__u64)le16_to_cpu(raw_inode->i_file_acl_high)) << 32;
}
inode->i_size = ext4_isize(raw_inode);
ei->i_disksize = inode->i_size;
inode->i_generation = le32_to_cpu(raw_inode->i_generation);
ei->i_block_group = iloc.block_group;
/*
* NOTE! The in-memory inode i_data array is in little-endian order
* even on big-endian machines: we do NOT byteswap the block numbers!
*/
for (block = 0; block < EXT4_N_BLOCKS; block++)
ei->i_data[block] = raw_inode->i_block[block];
INIT_LIST_HEAD(&ei->i_orphan);
if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
ei->i_extra_isize = le16_to_cpu(raw_inode->i_extra_isize);
if (EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize >
EXT4_INODE_SIZE(inode->i_sb)) {
brelse (bh);
ret = -EIO;
goto bad_inode;
}
if (ei->i_extra_isize == 0) {
/* The extra space is currently unused. Use it. */
ei->i_extra_isize = sizeof(struct ext4_inode) -
EXT4_GOOD_OLD_INODE_SIZE;
} else {
__le32 *magic = (void *)raw_inode +
EXT4_GOOD_OLD_INODE_SIZE +
ei->i_extra_isize;
if (*magic == cpu_to_le32(EXT4_XATTR_MAGIC))
ei->i_state |= EXT4_STATE_XATTR;
}
} else
ei->i_extra_isize = 0;
EXT4_INODE_GET_XTIME(i_ctime, inode, raw_inode);
EXT4_INODE_GET_XTIME(i_mtime, inode, raw_inode);
EXT4_INODE_GET_XTIME(i_atime, inode, raw_inode);
EXT4_EINODE_GET_XTIME(i_crtime, ei, raw_inode);
inode->i_version = le32_to_cpu(raw_inode->i_disk_version);
if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
if (EXT4_FITS_IN_INODE(raw_inode, ei, i_version_hi))
inode->i_version |=
(__u64)(le32_to_cpu(raw_inode->i_version_hi)) << 32;
}
if (S_ISREG(inode->i_mode)) {
inode->i_op = &ext4_file_inode_operations;
inode->i_fop = &ext4_file_operations;
ext4_set_aops(inode);
} else if (S_ISDIR(inode->i_mode)) {
inode->i_op = &ext4_dir_inode_operations;
inode->i_fop = &ext4_dir_operations;
} else if (S_ISLNK(inode->i_mode)) {
if (ext4_inode_is_fast_symlink(inode))
inode->i_op = &ext4_fast_symlink_inode_operations;
else {
inode->i_op = &ext4_symlink_inode_operations;
ext4_set_aops(inode);
}
} else {
inode->i_op = &ext4_special_inode_operations;
if (raw_inode->i_block[0])
init_special_inode(inode, inode->i_mode,
old_decode_dev(le32_to_cpu(raw_inode->i_block[0])));
else
init_special_inode(inode, inode->i_mode,
new_decode_dev(le32_to_cpu(raw_inode->i_block[1])));
}
brelse (iloc.bh);
ext4_set_inode_flags(inode);
unlock_new_inode(inode);
return inode;
bad_inode:
iget_failed(inode);
return ERR_PTR(ret);
}
static int ext4_inode_blocks_set(handle_t *handle,
struct ext4_inode *raw_inode,
struct ext4_inode_info *ei)
{
struct inode *inode = &(ei->vfs_inode);
u64 i_blocks = inode->i_blocks;
struct super_block *sb = inode->i_sb;
int err = 0;
if (i_blocks <= ~0U) {
/*
* i_blocks can be represnted in a 32 bit variable
* as multiple of 512 bytes
*/
raw_inode->i_blocks_lo = cpu_to_le32(i_blocks);
raw_inode->i_blocks_high = 0;
ei->i_flags &= ~EXT4_HUGE_FILE_FL;
} else if (i_blocks <= 0xffffffffffffULL) {
/*
* i_blocks can be represented in a 48 bit variable
* as multiple of 512 bytes
*/
err = ext4_update_rocompat_feature(handle, sb,
EXT4_FEATURE_RO_COMPAT_HUGE_FILE);
if (err)
goto err_out;
/* i_block is stored in the split 48 bit fields */
raw_inode->i_blocks_lo = cpu_to_le32(i_blocks);
raw_inode->i_blocks_high = cpu_to_le16(i_blocks >> 32);
ei->i_flags &= ~EXT4_HUGE_FILE_FL;
} else {
/*
* i_blocks should be represented in a 48 bit variable
* as multiple of file system block size
*/
err = ext4_update_rocompat_feature(handle, sb,
EXT4_FEATURE_RO_COMPAT_HUGE_FILE);
if (err)
goto err_out;
ei->i_flags |= EXT4_HUGE_FILE_FL;
/* i_block is stored in file system block size */
i_blocks = i_blocks >> (inode->i_blkbits - 9);
raw_inode->i_blocks_lo = cpu_to_le32(i_blocks);
raw_inode->i_blocks_high = cpu_to_le16(i_blocks >> 32);
}
err_out:
return err;
}
/*
* Post the struct inode info into an on-disk inode location in the
* buffer-cache. This gobbles the caller's reference to the
* buffer_head in the inode location struct.
*
* The caller must have write access to iloc->bh.
*/
static int ext4_do_update_inode(handle_t *handle,
struct inode *inode,
struct ext4_iloc *iloc)
{
struct ext4_inode *raw_inode = ext4_raw_inode(iloc);
struct ext4_inode_info *ei = EXT4_I(inode);
struct buffer_head *bh = iloc->bh;
int err = 0, rc, block;
/* For fields not not tracking in the in-memory inode,
* initialise them to zero for new inodes. */
if (ei->i_state & EXT4_STATE_NEW)
memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
ext4_get_inode_flags(ei);
raw_inode->i_mode = cpu_to_le16(inode->i_mode);
if(!(test_opt(inode->i_sb, NO_UID32))) {
raw_inode->i_uid_low = cpu_to_le16(low_16_bits(inode->i_uid));
raw_inode->i_gid_low = cpu_to_le16(low_16_bits(inode->i_gid));
/*
* Fix up interoperability with old kernels. Otherwise, old inodes get
* re-used with the upper 16 bits of the uid/gid intact
*/
if(!ei->i_dtime) {
raw_inode->i_uid_high =
cpu_to_le16(high_16_bits(inode->i_uid));
raw_inode->i_gid_high =
cpu_to_le16(high_16_bits(inode->i_gid));
} else {
raw_inode->i_uid_high = 0;
raw_inode->i_gid_high = 0;
}
} else {
raw_inode->i_uid_low =
cpu_to_le16(fs_high2lowuid(inode->i_uid));
raw_inode->i_gid_low =
cpu_to_le16(fs_high2lowgid(inode->i_gid));
raw_inode->i_uid_high = 0;
raw_inode->i_gid_high = 0;
}
raw_inode->i_links_count = cpu_to_le16(inode->i_nlink);
EXT4_INODE_SET_XTIME(i_ctime, inode, raw_inode);
EXT4_INODE_SET_XTIME(i_mtime, inode, raw_inode);
EXT4_INODE_SET_XTIME(i_atime, inode, raw_inode);
EXT4_EINODE_SET_XTIME(i_crtime, ei, raw_inode);
if (ext4_inode_blocks_set(handle, raw_inode, ei))
goto out_brelse;
raw_inode->i_dtime = cpu_to_le32(ei->i_dtime);
/* clear the migrate flag in the raw_inode */
raw_inode->i_flags = cpu_to_le32(ei->i_flags & ~EXT4_EXT_MIGRATE);
if (EXT4_SB(inode->i_sb)->s_es->s_creator_os !=
cpu_to_le32(EXT4_OS_HURD))
raw_inode->i_file_acl_high =
cpu_to_le16(ei->i_file_acl >> 32);
raw_inode->i_file_acl_lo = cpu_to_le32(ei->i_file_acl);
ext4_isize_set(raw_inode, ei->i_disksize);
if (ei->i_disksize > 0x7fffffffULL) {
struct super_block *sb = inode->i_sb;
if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
EXT4_FEATURE_RO_COMPAT_LARGE_FILE) ||
EXT4_SB(sb)->s_es->s_rev_level ==
cpu_to_le32(EXT4_GOOD_OLD_REV)) {
/* If this is the first large file
* created, add a flag to the superblock.
*/
err = ext4_journal_get_write_access(handle,
EXT4_SB(sb)->s_sbh);
if (err)
goto out_brelse;
ext4_update_dynamic_rev(sb);
EXT4_SET_RO_COMPAT_FEATURE(sb,
EXT4_FEATURE_RO_COMPAT_LARGE_FILE);
sb->s_dirt = 1;
handle->h_sync = 1;
err = ext4_journal_dirty_metadata(handle,
EXT4_SB(sb)->s_sbh);
}
}
raw_inode->i_generation = cpu_to_le32(inode->i_generation);
if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode)) {
if (old_valid_dev(inode->i_rdev)) {
raw_inode->i_block[0] =
cpu_to_le32(old_encode_dev(inode->i_rdev));
raw_inode->i_block[1] = 0;
} else {
raw_inode->i_block[0] = 0;
raw_inode->i_block[1] =
cpu_to_le32(new_encode_dev(inode->i_rdev));
raw_inode->i_block[2] = 0;
}
} else for (block = 0; block < EXT4_N_BLOCKS; block++)
raw_inode->i_block[block] = ei->i_data[block];
raw_inode->i_disk_version = cpu_to_le32(inode->i_version);
if (ei->i_extra_isize) {
if (EXT4_FITS_IN_INODE(raw_inode, ei, i_version_hi))
raw_inode->i_version_hi =
cpu_to_le32(inode->i_version >> 32);
raw_inode->i_extra_isize = cpu_to_le16(ei->i_extra_isize);
}
BUFFER_TRACE(bh, "call ext4_journal_dirty_metadata");
rc = ext4_journal_dirty_metadata(handle, bh);
if (!err)
err = rc;
ei->i_state &= ~EXT4_STATE_NEW;
out_brelse:
brelse (bh);
ext4_std_error(inode->i_sb, err);
return err;
}
/*
* ext4_write_inode()
*
* We are called from a few places:
*
* - Within generic_file_write() for O_SYNC files.
* Here, there will be no transaction running. We wait for any running
* trasnaction to commit.
*
* - Within sys_sync(), kupdate and such.
* We wait on commit, if tol to.
*
* - Within prune_icache() (PF_MEMALLOC == true)
* Here we simply return. We can't afford to block kswapd on the
* journal commit.
*
* In all cases it is actually safe for us to return without doing anything,
* because the inode has been copied into a raw inode buffer in
* ext4_mark_inode_dirty(). This is a correctness thing for O_SYNC and for
* knfsd.
*
* Note that we are absolutely dependent upon all inode dirtiers doing the
* right thing: they *must* call mark_inode_dirty() after dirtying info in
* which we are interested.
*
* It would be a bug for them to not do this. The code:
*
* mark_inode_dirty(inode)
* stuff();
* inode->i_size = expr;
*
* is in error because a kswapd-driven write_inode() could occur while
* `stuff()' is running, and the new i_size will be lost. Plus the inode
* will no longer be on the superblock's dirty inode list.
*/
int ext4_write_inode(struct inode *inode, int wait)
{
if (current->flags & PF_MEMALLOC)
return 0;
if (ext4_journal_current_handle()) {
jbd_debug(1, "called recursively, non-PF_MEMALLOC!\n");
dump_stack();
return -EIO;
}
if (!wait)
return 0;
return ext4_force_commit(inode->i_sb);
}
/*
* ext4_setattr()
*
* Called from notify_change.
*
* We want to trap VFS attempts to truncate the file as soon as
* possible. In particular, we want to make sure that when the VFS
* shrinks i_size, we put the inode on the orphan list and modify
* i_disksize immediately, so that during the subsequent flushing of
* dirty pages and freeing of disk blocks, we can guarantee that any
* commit will leave the blocks being flushed in an unused state on
* disk. (On recovery, the inode will get truncated and the blocks will
* be freed, so we have a strong guarantee that no future commit will
* leave these blocks visible to the user.)
*
* Called with inode->sem down.
*/
int ext4_setattr(struct dentry *dentry, struct iattr *attr)
{
struct inode *inode = dentry->d_inode;
int error, rc = 0;
const unsigned int ia_valid = attr->ia_valid;
error = inode_change_ok(inode, attr);
if (error)
return error;
if ((ia_valid & ATTR_UID && attr->ia_uid != inode->i_uid) ||
(ia_valid & ATTR_GID && attr->ia_gid != inode->i_gid)) {
handle_t *handle;
/* (user+group)*(old+new) structure, inode write (sb,
* inode block, ? - but truncate inode update has it) */
handle = ext4_journal_start(inode, 2*(EXT4_QUOTA_INIT_BLOCKS(inode->i_sb)+
EXT4_QUOTA_DEL_BLOCKS(inode->i_sb))+3);
if (IS_ERR(handle)) {
error = PTR_ERR(handle);
goto err_out;
}
error = DQUOT_TRANSFER(inode, attr) ? -EDQUOT : 0;
if (error) {
ext4_journal_stop(handle);
return error;
}
/* Update corresponding info in inode so that everything is in
* one transaction */
if (attr->ia_valid & ATTR_UID)
inode->i_uid = attr->ia_uid;
if (attr->ia_valid & ATTR_GID)
inode->i_gid = attr->ia_gid;
error = ext4_mark_inode_dirty(handle, inode);
ext4_journal_stop(handle);
}
if (attr->ia_valid & ATTR_SIZE) {
if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)) {
struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
if (attr->ia_size > sbi->s_bitmap_maxbytes) {
error = -EFBIG;
goto err_out;
}
}
}
if (S_ISREG(inode->i_mode) &&
attr->ia_valid & ATTR_SIZE && attr->ia_size < inode->i_size) {
handle_t *handle;
handle = ext4_journal_start(inode, 3);
if (IS_ERR(handle)) {
error = PTR_ERR(handle);
goto err_out;
}
error = ext4_orphan_add(handle, inode);
EXT4_I(inode)->i_disksize = attr->ia_size;
rc = ext4_mark_inode_dirty(handle, inode);
if (!error)
error = rc;
ext4_journal_stop(handle);
}
rc = inode_setattr(inode, attr);
/* If inode_setattr's call to ext4_truncate failed to get a
* transaction handle at all, we need to clean up the in-core
* orphan list manually. */
if (inode->i_nlink)
ext4_orphan_del(NULL, inode);
if (!rc && (ia_valid & ATTR_MODE))
rc = ext4_acl_chmod(inode);
err_out:
ext4_std_error(inode->i_sb, error);
if (!error)
error = rc;
return error;
}
/*
* How many blocks doth make a writepage()?
*
* With N blocks per page, it may be:
* N data blocks
* 2 indirect block
* 2 dindirect
* 1 tindirect
* N+5 bitmap blocks (from the above)
* N+5 group descriptor summary blocks
* 1 inode block
* 1 superblock.
* 2 * EXT4_SINGLEDATA_TRANS_BLOCKS for the quote files
*
* 3 * (N + 5) + 2 + 2 * EXT4_SINGLEDATA_TRANS_BLOCKS
*
* With ordered or writeback data it's the same, less the N data blocks.
*
* If the inode's direct blocks can hold an integral number of pages then a
* page cannot straddle two indirect blocks, and we can only touch one indirect
* and dindirect block, and the "5" above becomes "3".
*
* This still overestimates under most circumstances. If we were to pass the
* start and end offsets in here as well we could do block_to_path() on each
* block and work out the exact number of indirects which are touched. Pah.
*/
int ext4_writepage_trans_blocks(struct inode *inode)
{
int bpp = ext4_journal_blocks_per_page(inode);
int indirects = (EXT4_NDIR_BLOCKS % bpp) ? 5 : 3;
int ret;
if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)
return ext4_ext_writepage_trans_blocks(inode, bpp);
if (ext4_should_journal_data(inode))
ret = 3 * (bpp + indirects) + 2;
else
ret = 2 * (bpp + indirects) + 2;
#ifdef CONFIG_QUOTA
/* We know that structure was already allocated during DQUOT_INIT so
* we will be updating only the data blocks + inodes */
ret += 2*EXT4_QUOTA_TRANS_BLOCKS(inode->i_sb);
#endif
return ret;
}
/*
* The caller must have previously called ext4_reserve_inode_write().
* Give this, we know that the caller already has write access to iloc->bh.
*/
int ext4_mark_iloc_dirty(handle_t *handle,
struct inode *inode, struct ext4_iloc *iloc)
{
int err = 0;
if (test_opt(inode->i_sb, I_VERSION))
inode_inc_iversion(inode);
/* the do_update_inode consumes one bh->b_count */
get_bh(iloc->bh);
/* ext4_do_update_inode() does jbd2_journal_dirty_metadata */
err = ext4_do_update_inode(handle, inode, iloc);
put_bh(iloc->bh);
return err;
}
/*
* On success, We end up with an outstanding reference count against
* iloc->bh. This _must_ be cleaned up later.
*/
int
ext4_reserve_inode_write(handle_t *handle, struct inode *inode,
struct ext4_iloc *iloc)
{
int err = 0;
if (handle) {
err = ext4_get_inode_loc(inode, iloc);
if (!err) {
BUFFER_TRACE(iloc->bh, "get_write_access");
err = ext4_journal_get_write_access(handle, iloc->bh);
if (err) {
brelse(iloc->bh);
iloc->bh = NULL;
}
}
}
ext4_std_error(inode->i_sb, err);
return err;
}
/*
* Expand an inode by new_extra_isize bytes.
* Returns 0 on success or negative error number on failure.
*/
static int ext4_expand_extra_isize(struct inode *inode,
unsigned int new_extra_isize,
struct ext4_iloc iloc,
handle_t *handle)
{
struct ext4_inode *raw_inode;
struct ext4_xattr_ibody_header *header;
struct ext4_xattr_entry *entry;
if (EXT4_I(inode)->i_extra_isize >= new_extra_isize)
return 0;
raw_inode = ext4_raw_inode(&iloc);
header = IHDR(inode, raw_inode);
entry = IFIRST(header);
/* No extended attributes present */
if (!(EXT4_I(inode)->i_state & EXT4_STATE_XATTR) ||
header->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC)) {
memset((void *)raw_inode + EXT4_GOOD_OLD_INODE_SIZE, 0,
new_extra_isize);
EXT4_I(inode)->i_extra_isize = new_extra_isize;
return 0;
}
/* try to expand with EAs present */
return ext4_expand_extra_isize_ea(inode, new_extra_isize,
raw_inode, handle);
}
/*
* What we do here is to mark the in-core inode as clean with respect to inode
* dirtiness (it may still be data-dirty).
* This means that the in-core inode may be reaped by prune_icache
* without having to perform any I/O. This is a very good thing,
* because *any* task may call prune_icache - even ones which
* have a transaction open against a different journal.
*
* Is this cheating? Not really. Sure, we haven't written the
* inode out, but prune_icache isn't a user-visible syncing function.
* Whenever the user wants stuff synced (sys_sync, sys_msync, sys_fsync)
* we start and wait on commits.
*
* Is this efficient/effective? Well, we're being nice to the system
* by cleaning up our inodes proactively so they can be reaped
* without I/O. But we are potentially leaving up to five seconds'
* worth of inodes floating about which prune_icache wants us to
* write out. One way to fix that would be to get prune_icache()
* to do a write_super() to free up some memory. It has the desired
* effect.
*/
int ext4_mark_inode_dirty(handle_t *handle, struct inode *inode)
{
struct ext4_iloc iloc;
struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
static unsigned int mnt_count;
int err, ret;
might_sleep();
err = ext4_reserve_inode_write(handle, inode, &iloc);
if (EXT4_I(inode)->i_extra_isize < sbi->s_want_extra_isize &&
!(EXT4_I(inode)->i_state & EXT4_STATE_NO_EXPAND)) {
/*
* We need extra buffer credits since we may write into EA block
* with this same handle. If journal_extend fails, then it will
* only result in a minor loss of functionality for that inode.
* If this is felt to be critical, then e2fsck should be run to
* force a large enough s_min_extra_isize.
*/
if ((jbd2_journal_extend(handle,
EXT4_DATA_TRANS_BLOCKS(inode->i_sb))) == 0) {
ret = ext4_expand_extra_isize(inode,
sbi->s_want_extra_isize,
iloc, handle);
if (ret) {
EXT4_I(inode)->i_state |= EXT4_STATE_NO_EXPAND;
if (mnt_count !=
le16_to_cpu(sbi->s_es->s_mnt_count)) {
ext4_warning(inode->i_sb, __func__,
"Unable to expand inode %lu. Delete"
" some EAs or run e2fsck.",
inode->i_ino);
mnt_count =
le16_to_cpu(sbi->s_es->s_mnt_count);
}
}
}
}
if (!err)
err = ext4_mark_iloc_dirty(handle, inode, &iloc);
return err;
}
/*
* ext4_dirty_inode() is called from __mark_inode_dirty()
*
* We're really interested in the case where a file is being extended.
* i_size has been changed by generic_commit_write() and we thus need
* to include the updated inode in the current transaction.
*
* Also, DQUOT_ALLOC_SPACE() will always dirty the inode when blocks
* are allocated to the file.
*
* If the inode is marked synchronous, we don't honour that here - doing
* so would cause a commit on atime updates, which we don't bother doing.
* We handle synchronous inodes at the highest possible level.
*/
void ext4_dirty_inode(struct inode *inode)
{
handle_t *current_handle = ext4_journal_current_handle();
handle_t *handle;
handle = ext4_journal_start(inode, 2);
if (IS_ERR(handle))
goto out;
if (current_handle &&
current_handle->h_transaction != handle->h_transaction) {
/* This task has a transaction open against a different fs */
printk(KERN_EMERG "%s: transactions do not match!\n",
__func__);
} else {
jbd_debug(5, "marking dirty. outer handle=%p\n",
current_handle);
ext4_mark_inode_dirty(handle, inode);
}
ext4_journal_stop(handle);
out:
return;
}
#if 0
/*
* Bind an inode's backing buffer_head into this transaction, to prevent
* it from being flushed to disk early. Unlike
* ext4_reserve_inode_write, this leaves behind no bh reference and
* returns no iloc structure, so the caller needs to repeat the iloc
* lookup to mark the inode dirty later.
*/
static int ext4_pin_inode(handle_t *handle, struct inode *inode)
{
struct ext4_iloc iloc;
int err = 0;
if (handle) {
err = ext4_get_inode_loc(inode, &iloc);
if (!err) {
BUFFER_TRACE(iloc.bh, "get_write_access");
err = jbd2_journal_get_write_access(handle, iloc.bh);
if (!err)
err = ext4_journal_dirty_metadata(handle,
iloc.bh);
brelse(iloc.bh);
}
}
ext4_std_error(inode->i_sb, err);
return err;
}
#endif
int ext4_change_inode_journal_flag(struct inode *inode, int val)
{
journal_t *journal;
handle_t *handle;
int err;
/*
* We have to be very careful here: changing a data block's
* journaling status dynamically is dangerous. If we write a
* data block to the journal, change the status and then delete
* that block, we risk forgetting to revoke the old log record
* from the journal and so a subsequent replay can corrupt data.
* So, first we make sure that the journal is empty and that
* nobody is changing anything.
*/
journal = EXT4_JOURNAL(inode);
if (is_journal_aborted(journal))
return -EROFS;
jbd2_journal_lock_updates(journal);
jbd2_journal_flush(journal);
/*
* OK, there are no updates running now, and all cached data is
* synced to disk. We are now in a completely consistent state
* which doesn't have anything in the journal, and we know that
* no filesystem updates are running, so it is safe to modify
* the inode's in-core data-journaling state flag now.
*/
if (val)
EXT4_I(inode)->i_flags |= EXT4_JOURNAL_DATA_FL;
else
EXT4_I(inode)->i_flags &= ~EXT4_JOURNAL_DATA_FL;
ext4_set_aops(inode);
jbd2_journal_unlock_updates(journal);
/* Finally we can mark the inode as dirty. */
handle = ext4_journal_start(inode, 1);
if (IS_ERR(handle))
return PTR_ERR(handle);
err = ext4_mark_inode_dirty(handle, inode);
handle->h_sync = 1;
ext4_journal_stop(handle);
ext4_std_error(inode->i_sb, err);
return err;
}
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