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OpenCloudOS-Kernel/fs/ext4/extents.c

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/*
* Copyright (c) 2003-2006, Cluster File Systems, Inc, info@clusterfs.com
* Written by Alex Tomas <alex@clusterfs.com>
*
* Architecture independence:
* Copyright (c) 2005, Bull S.A.
* Written by Pierre Peiffer <pierre.peiffer@bull.net>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public Licens
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-
*/
/*
* Extents support for EXT4
*
* TODO:
* - ext4*_error() should be used in some situations
* - analyze all BUG()/BUG_ON(), use -EIO where appropriate
* - smart tree reduction
*/
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/time.h>
#include <linux/ext4_jbd2.h>
#include <linux/jbd2.h>
#include <linux/highuid.h>
#include <linux/pagemap.h>
#include <linux/quotaops.h>
#include <linux/string.h>
#include <linux/slab.h>
#include <linux/falloc.h>
#include <linux/ext4_fs_extents.h>
#include <asm/uaccess.h>
/*
* ext_pblock:
* combine low and high parts of physical block number into ext4_fsblk_t
*/
static ext4_fsblk_t ext_pblock(struct ext4_extent *ex)
{
ext4_fsblk_t block;
block = le32_to_cpu(ex->ee_start_lo);
block |= ((ext4_fsblk_t) le16_to_cpu(ex->ee_start_hi) << 31) << 1;
return block;
}
/*
* idx_pblock:
* combine low and high parts of a leaf physical block number into ext4_fsblk_t
*/
static ext4_fsblk_t idx_pblock(struct ext4_extent_idx *ix)
{
ext4_fsblk_t block;
block = le32_to_cpu(ix->ei_leaf_lo);
block |= ((ext4_fsblk_t) le16_to_cpu(ix->ei_leaf_hi) << 31) << 1;
return block;
}
/*
* ext4_ext_store_pblock:
* stores a large physical block number into an extent struct,
* breaking it into parts
*/
static void ext4_ext_store_pblock(struct ext4_extent *ex, ext4_fsblk_t pb)
{
ex->ee_start_lo = cpu_to_le32((unsigned long) (pb & 0xffffffff));
ex->ee_start_hi = cpu_to_le16((unsigned long) ((pb >> 31) >> 1) & 0xffff);
}
/*
* ext4_idx_store_pblock:
* stores a large physical block number into an index struct,
* breaking it into parts
*/
static void ext4_idx_store_pblock(struct ext4_extent_idx *ix, ext4_fsblk_t pb)
{
ix->ei_leaf_lo = cpu_to_le32((unsigned long) (pb & 0xffffffff));
ix->ei_leaf_hi = cpu_to_le16((unsigned long) ((pb >> 31) >> 1) & 0xffff);
}
static handle_t *ext4_ext_journal_restart(handle_t *handle, int needed)
{
int err;
if (handle->h_buffer_credits > needed)
return handle;
if (!ext4_journal_extend(handle, needed))
return handle;
err = ext4_journal_restart(handle, needed);
return handle;
}
/*
* could return:
* - EROFS
* - ENOMEM
*/
static int ext4_ext_get_access(handle_t *handle, struct inode *inode,
struct ext4_ext_path *path)
{
if (path->p_bh) {
/* path points to block */
return ext4_journal_get_write_access(handle, path->p_bh);
}
/* path points to leaf/index in inode body */
/* we use in-core data, no need to protect them */
return 0;
}
/*
* could return:
* - EROFS
* - ENOMEM
* - EIO
*/
static int ext4_ext_dirty(handle_t *handle, struct inode *inode,
struct ext4_ext_path *path)
{
int err;
if (path->p_bh) {
/* path points to block */
err = ext4_journal_dirty_metadata(handle, path->p_bh);
} else {
/* path points to leaf/index in inode body */
err = ext4_mark_inode_dirty(handle, inode);
}
return err;
}
static ext4_fsblk_t ext4_ext_find_goal(struct inode *inode,
struct ext4_ext_path *path,
ext4_lblk_t block)
{
struct ext4_inode_info *ei = EXT4_I(inode);
ext4_fsblk_t bg_start;
ext4_grpblk_t colour;
int depth;
if (path) {
struct ext4_extent *ex;
depth = path->p_depth;
/* try to predict block placement */
ex = path[depth].p_ext;
if (ex)
return ext_pblock(ex)+(block-le32_to_cpu(ex->ee_block));
/* it looks like index is empty;
* try to find starting block from index itself */
if (path[depth].p_bh)
return path[depth].p_bh->b_blocknr;
}
/* OK. use inode's group */
bg_start = (ei->i_block_group * EXT4_BLOCKS_PER_GROUP(inode->i_sb)) +
le32_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_first_data_block);
colour = (current->pid % 16) *
(EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16);
return bg_start + colour + block;
}
static ext4_fsblk_t
ext4_ext_new_block(handle_t *handle, struct inode *inode,
struct ext4_ext_path *path,
struct ext4_extent *ex, int *err)
{
ext4_fsblk_t goal, newblock;
goal = ext4_ext_find_goal(inode, path, le32_to_cpu(ex->ee_block));
newblock = ext4_new_block(handle, inode, goal, err);
return newblock;
}
static int ext4_ext_space_block(struct inode *inode)
{
int size;
size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
/ sizeof(struct ext4_extent);
#ifdef AGGRESSIVE_TEST
if (size > 6)
size = 6;
#endif
return size;
}
static int ext4_ext_space_block_idx(struct inode *inode)
{
int size;
size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
/ sizeof(struct ext4_extent_idx);
#ifdef AGGRESSIVE_TEST
if (size > 5)
size = 5;
#endif
return size;
}
static int ext4_ext_space_root(struct inode *inode)
{
int size;
size = sizeof(EXT4_I(inode)->i_data);
size -= sizeof(struct ext4_extent_header);
size /= sizeof(struct ext4_extent);
#ifdef AGGRESSIVE_TEST
if (size > 3)
size = 3;
#endif
return size;
}
static int ext4_ext_space_root_idx(struct inode *inode)
{
int size;
size = sizeof(EXT4_I(inode)->i_data);
size -= sizeof(struct ext4_extent_header);
size /= sizeof(struct ext4_extent_idx);
#ifdef AGGRESSIVE_TEST
if (size > 4)
size = 4;
#endif
return size;
}
static int
ext4_ext_max_entries(struct inode *inode, int depth)
{
int max;
if (depth == ext_depth(inode)) {
if (depth == 0)
max = ext4_ext_space_root(inode);
else
max = ext4_ext_space_root_idx(inode);
} else {
if (depth == 0)
max = ext4_ext_space_block(inode);
else
max = ext4_ext_space_block_idx(inode);
}
return max;
}
static int __ext4_ext_check_header(const char *function, struct inode *inode,
struct ext4_extent_header *eh,
int depth)
{
const char *error_msg;
int max = 0;
if (unlikely(eh->eh_magic != EXT4_EXT_MAGIC)) {
error_msg = "invalid magic";
goto corrupted;
}
if (unlikely(le16_to_cpu(eh->eh_depth) != depth)) {
error_msg = "unexpected eh_depth";
goto corrupted;
}
if (unlikely(eh->eh_max == 0)) {
error_msg = "invalid eh_max";
goto corrupted;
}
max = ext4_ext_max_entries(inode, depth);
if (unlikely(le16_to_cpu(eh->eh_max) > max)) {
error_msg = "too large eh_max";
goto corrupted;
}
if (unlikely(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max))) {
error_msg = "invalid eh_entries";
goto corrupted;
}
return 0;
corrupted:
ext4_error(inode->i_sb, function,
"bad header in inode #%lu: %s - magic %x, "
"entries %u, max %u(%u), depth %u(%u)",
inode->i_ino, error_msg, le16_to_cpu(eh->eh_magic),
le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max),
max, le16_to_cpu(eh->eh_depth), depth);
return -EIO;
}
#define ext4_ext_check_header(inode, eh, depth) \
__ext4_ext_check_header(__FUNCTION__, inode, eh, depth)
#ifdef EXT_DEBUG
static void ext4_ext_show_path(struct inode *inode, struct ext4_ext_path *path)
{
int k, l = path->p_depth;
ext_debug("path:");
for (k = 0; k <= l; k++, path++) {
if (path->p_idx) {
ext_debug(" %d->%llu", le32_to_cpu(path->p_idx->ei_block),
idx_pblock(path->p_idx));
} else if (path->p_ext) {
ext_debug(" %d:%d:%llu ",
le32_to_cpu(path->p_ext->ee_block),
ext4_ext_get_actual_len(path->p_ext),
ext_pblock(path->p_ext));
} else
ext_debug(" []");
}
ext_debug("\n");
}
static void ext4_ext_show_leaf(struct inode *inode, struct ext4_ext_path *path)
{
int depth = ext_depth(inode);
struct ext4_extent_header *eh;
struct ext4_extent *ex;
int i;
if (!path)
return;
eh = path[depth].p_hdr;
ex = EXT_FIRST_EXTENT(eh);
for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ex++) {
ext_debug("%d:%d:%llu ", le32_to_cpu(ex->ee_block),
ext4_ext_get_actual_len(ex), ext_pblock(ex));
}
ext_debug("\n");
}
#else
#define ext4_ext_show_path(inode,path)
#define ext4_ext_show_leaf(inode,path)
#endif
static void ext4_ext_drop_refs(struct ext4_ext_path *path)
{
int depth = path->p_depth;
int i;
for (i = 0; i <= depth; i++, path++)
if (path->p_bh) {
brelse(path->p_bh);
path->p_bh = NULL;
}
}
/*
* ext4_ext_binsearch_idx:
* binary search for the closest index of the given block
* the header must be checked before calling this
*/
static void
ext4_ext_binsearch_idx(struct inode *inode,
struct ext4_ext_path *path, ext4_lblk_t block)
{
struct ext4_extent_header *eh = path->p_hdr;
struct ext4_extent_idx *r, *l, *m;
ext_debug("binsearch for %u(idx): ", block);
l = EXT_FIRST_INDEX(eh) + 1;
r = EXT_LAST_INDEX(eh);
while (l <= r) {
m = l + (r - l) / 2;
if (block < le32_to_cpu(m->ei_block))
r = m - 1;
else
l = m + 1;
ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ei_block),
m, le32_to_cpu(m->ei_block),
r, le32_to_cpu(r->ei_block));
}
path->p_idx = l - 1;
ext_debug(" -> %d->%lld ", le32_to_cpu(path->p_idx->ei_block),
idx_pblock(path->p_idx));
#ifdef CHECK_BINSEARCH
{
struct ext4_extent_idx *chix, *ix;
int k;
chix = ix = EXT_FIRST_INDEX(eh);
for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ix++) {
if (k != 0 &&
le32_to_cpu(ix->ei_block) <= le32_to_cpu(ix[-1].ei_block)) {
printk("k=%d, ix=0x%p, first=0x%p\n", k,
ix, EXT_FIRST_INDEX(eh));
printk("%u <= %u\n",
le32_to_cpu(ix->ei_block),
le32_to_cpu(ix[-1].ei_block));
}
BUG_ON(k && le32_to_cpu(ix->ei_block)
<= le32_to_cpu(ix[-1].ei_block));
if (block < le32_to_cpu(ix->ei_block))
break;
chix = ix;
}
BUG_ON(chix != path->p_idx);
}
#endif
}
/*
* ext4_ext_binsearch:
* binary search for closest extent of the given block
* the header must be checked before calling this
*/
static void
ext4_ext_binsearch(struct inode *inode,
struct ext4_ext_path *path, ext4_lblk_t block)
{
struct ext4_extent_header *eh = path->p_hdr;
struct ext4_extent *r, *l, *m;
if (eh->eh_entries == 0) {
/*
* this leaf is empty:
* we get such a leaf in split/add case
*/
return;
}
ext_debug("binsearch for %u: ", block);
l = EXT_FIRST_EXTENT(eh) + 1;
r = EXT_LAST_EXTENT(eh);
while (l <= r) {
m = l + (r - l) / 2;
if (block < le32_to_cpu(m->ee_block))
r = m - 1;
else
l = m + 1;
ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ee_block),
m, le32_to_cpu(m->ee_block),
r, le32_to_cpu(r->ee_block));
}
path->p_ext = l - 1;
ext_debug(" -> %d:%llu:%d ",
le32_to_cpu(path->p_ext->ee_block),
ext_pblock(path->p_ext),
ext4_ext_get_actual_len(path->p_ext));
#ifdef CHECK_BINSEARCH
{
struct ext4_extent *chex, *ex;
int k;
chex = ex = EXT_FIRST_EXTENT(eh);
for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ex++) {
BUG_ON(k && le32_to_cpu(ex->ee_block)
<= le32_to_cpu(ex[-1].ee_block));
if (block < le32_to_cpu(ex->ee_block))
break;
chex = ex;
}
BUG_ON(chex != path->p_ext);
}
#endif
}
int ext4_ext_tree_init(handle_t *handle, struct inode *inode)
{
struct ext4_extent_header *eh;
eh = ext_inode_hdr(inode);
eh->eh_depth = 0;
eh->eh_entries = 0;
eh->eh_magic = EXT4_EXT_MAGIC;
eh->eh_max = cpu_to_le16(ext4_ext_space_root(inode));
ext4_mark_inode_dirty(handle, inode);
ext4_ext_invalidate_cache(inode);
return 0;
}
struct ext4_ext_path *
ext4_ext_find_extent(struct inode *inode, ext4_lblk_t block,
struct ext4_ext_path *path)
{
struct ext4_extent_header *eh;
struct buffer_head *bh;
short int depth, i, ppos = 0, alloc = 0;
eh = ext_inode_hdr(inode);
depth = ext_depth(inode);
if (ext4_ext_check_header(inode, eh, depth))
return ERR_PTR(-EIO);
/* account possible depth increase */
if (!path) {
path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 2),
GFP_NOFS);
if (!path)
return ERR_PTR(-ENOMEM);
alloc = 1;
}
path[0].p_hdr = eh;
i = depth;
/* walk through the tree */
while (i) {
ext_debug("depth %d: num %d, max %d\n",
ppos, le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
ext4_ext_binsearch_idx(inode, path + ppos, block);
path[ppos].p_block = idx_pblock(path[ppos].p_idx);
path[ppos].p_depth = i;
path[ppos].p_ext = NULL;
bh = sb_bread(inode->i_sb, path[ppos].p_block);
if (!bh)
goto err;
eh = ext_block_hdr(bh);
ppos++;
BUG_ON(ppos > depth);
path[ppos].p_bh = bh;
path[ppos].p_hdr = eh;
i--;
if (ext4_ext_check_header(inode, eh, i))
goto err;
}
path[ppos].p_depth = i;
path[ppos].p_hdr = eh;
path[ppos].p_ext = NULL;
path[ppos].p_idx = NULL;
/* find extent */
ext4_ext_binsearch(inode, path + ppos, block);
ext4_ext_show_path(inode, path);
return path;
err:
ext4_ext_drop_refs(path);
if (alloc)
kfree(path);
return ERR_PTR(-EIO);
}
/*
* ext4_ext_insert_index:
* insert new index [@logical;@ptr] into the block at @curp;
* check where to insert: before @curp or after @curp
*/
static int ext4_ext_insert_index(handle_t *handle, struct inode *inode,
struct ext4_ext_path *curp,
int logical, ext4_fsblk_t ptr)
{
struct ext4_extent_idx *ix;
int len, err;
err = ext4_ext_get_access(handle, inode, curp);
if (err)
return err;
BUG_ON(logical == le32_to_cpu(curp->p_idx->ei_block));
len = EXT_MAX_INDEX(curp->p_hdr) - curp->p_idx;
if (logical > le32_to_cpu(curp->p_idx->ei_block)) {
/* insert after */
if (curp->p_idx != EXT_LAST_INDEX(curp->p_hdr)) {
len = (len - 1) * sizeof(struct ext4_extent_idx);
len = len < 0 ? 0 : len;
ext_debug("insert new index %d after: %llu. "
"move %d from 0x%p to 0x%p\n",
logical, ptr, len,
(curp->p_idx + 1), (curp->p_idx + 2));
memmove(curp->p_idx + 2, curp->p_idx + 1, len);
}
ix = curp->p_idx + 1;
} else {
/* insert before */
len = len * sizeof(struct ext4_extent_idx);
len = len < 0 ? 0 : len;
ext_debug("insert new index %d before: %llu. "
"move %d from 0x%p to 0x%p\n",
logical, ptr, len,
curp->p_idx, (curp->p_idx + 1));
memmove(curp->p_idx + 1, curp->p_idx, len);
ix = curp->p_idx;
}
ix->ei_block = cpu_to_le32(logical);
ext4_idx_store_pblock(ix, ptr);
curp->p_hdr->eh_entries = cpu_to_le16(le16_to_cpu(curp->p_hdr->eh_entries)+1);
BUG_ON(le16_to_cpu(curp->p_hdr->eh_entries)
> le16_to_cpu(curp->p_hdr->eh_max));
BUG_ON(ix > EXT_LAST_INDEX(curp->p_hdr));
err = ext4_ext_dirty(handle, inode, curp);
ext4_std_error(inode->i_sb, err);
return err;
}
/*
* ext4_ext_split:
* inserts new subtree into the path, using free index entry
* at depth @at:
* - allocates all needed blocks (new leaf and all intermediate index blocks)
* - makes decision where to split
* - moves remaining extents and index entries (right to the split point)
* into the newly allocated blocks
* - initializes subtree
*/
static int ext4_ext_split(handle_t *handle, struct inode *inode,
struct ext4_ext_path *path,
struct ext4_extent *newext, int at)
{
struct buffer_head *bh = NULL;
int depth = ext_depth(inode);
struct ext4_extent_header *neh;
struct ext4_extent_idx *fidx;
struct ext4_extent *ex;
int i = at, k, m, a;
ext4_fsblk_t newblock, oldblock;
__le32 border;
ext4_fsblk_t *ablocks = NULL; /* array of allocated blocks */
int err = 0;
/* make decision: where to split? */
/* FIXME: now decision is simplest: at current extent */
/* if current leaf will be split, then we should use
* border from split point */
BUG_ON(path[depth].p_ext > EXT_MAX_EXTENT(path[depth].p_hdr));
if (path[depth].p_ext != EXT_MAX_EXTENT(path[depth].p_hdr)) {
border = path[depth].p_ext[1].ee_block;
ext_debug("leaf will be split."
" next leaf starts at %d\n",
le32_to_cpu(border));
} else {
border = newext->ee_block;
ext_debug("leaf will be added."
" next leaf starts at %d\n",
le32_to_cpu(border));
}
/*
* If error occurs, then we break processing
* and mark filesystem read-only. index won't
* be inserted and tree will be in consistent
* state. Next mount will repair buffers too.
*/
/*
* Get array to track all allocated blocks.
* We need this to handle errors and free blocks
* upon them.
*/
ablocks = kzalloc(sizeof(ext4_fsblk_t) * depth, GFP_NOFS);
if (!ablocks)
return -ENOMEM;
/* allocate all needed blocks */
ext_debug("allocate %d blocks for indexes/leaf\n", depth - at);
for (a = 0; a < depth - at; a++) {
newblock = ext4_ext_new_block(handle, inode, path, newext, &err);
if (newblock == 0)
goto cleanup;
ablocks[a] = newblock;
}
/* initialize new leaf */
newblock = ablocks[--a];
BUG_ON(newblock == 0);
bh = sb_getblk(inode->i_sb, newblock);
if (!bh) {
err = -EIO;
goto cleanup;
}
lock_buffer(bh);
err = ext4_journal_get_create_access(handle, bh);
if (err)
goto cleanup;
neh = ext_block_hdr(bh);
neh->eh_entries = 0;
neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode));
neh->eh_magic = EXT4_EXT_MAGIC;
neh->eh_depth = 0;
ex = EXT_FIRST_EXTENT(neh);
/* move remainder of path[depth] to the new leaf */
BUG_ON(path[depth].p_hdr->eh_entries != path[depth].p_hdr->eh_max);
/* start copy from next extent */
/* TODO: we could do it by single memmove */
m = 0;
path[depth].p_ext++;
while (path[depth].p_ext <=
EXT_MAX_EXTENT(path[depth].p_hdr)) {
ext_debug("move %d:%llu:%d in new leaf %llu\n",
le32_to_cpu(path[depth].p_ext->ee_block),
ext_pblock(path[depth].p_ext),
ext4_ext_get_actual_len(path[depth].p_ext),
newblock);
/*memmove(ex++, path[depth].p_ext++,
sizeof(struct ext4_extent));
neh->eh_entries++;*/
path[depth].p_ext++;
m++;
}
if (m) {
memmove(ex, path[depth].p_ext-m, sizeof(struct ext4_extent)*m);
neh->eh_entries = cpu_to_le16(le16_to_cpu(neh->eh_entries)+m);
}
set_buffer_uptodate(bh);
unlock_buffer(bh);
err = ext4_journal_dirty_metadata(handle, bh);
if (err)
goto cleanup;
brelse(bh);
bh = NULL;
/* correct old leaf */
if (m) {
err = ext4_ext_get_access(handle, inode, path + depth);
if (err)
goto cleanup;
path[depth].p_hdr->eh_entries =
cpu_to_le16(le16_to_cpu(path[depth].p_hdr->eh_entries)-m);
err = ext4_ext_dirty(handle, inode, path + depth);
if (err)
goto cleanup;
}
/* create intermediate indexes */
k = depth - at - 1;
BUG_ON(k < 0);
if (k)
ext_debug("create %d intermediate indices\n", k);
/* insert new index into current index block */
/* current depth stored in i var */
i = depth - 1;
while (k--) {
oldblock = newblock;
newblock = ablocks[--a];
bh = sb_getblk(inode->i_sb, newblock);
if (!bh) {
err = -EIO;
goto cleanup;
}
lock_buffer(bh);
err = ext4_journal_get_create_access(handle, bh);
if (err)
goto cleanup;
neh = ext_block_hdr(bh);
neh->eh_entries = cpu_to_le16(1);
neh->eh_magic = EXT4_EXT_MAGIC;
neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode));
neh->eh_depth = cpu_to_le16(depth - i);
fidx = EXT_FIRST_INDEX(neh);
fidx->ei_block = border;
ext4_idx_store_pblock(fidx, oldblock);
ext_debug("int.index at %d (block %llu): %u -> %llu\n",
i, newblock, le32_to_cpu(border), oldblock);
/* copy indexes */
m = 0;
path[i].p_idx++;
ext_debug("cur 0x%p, last 0x%p\n", path[i].p_idx,
EXT_MAX_INDEX(path[i].p_hdr));
BUG_ON(EXT_MAX_INDEX(path[i].p_hdr) !=
EXT_LAST_INDEX(path[i].p_hdr));
while (path[i].p_idx <= EXT_MAX_INDEX(path[i].p_hdr)) {
ext_debug("%d: move %d:%llu in new index %llu\n", i,
le32_to_cpu(path[i].p_idx->ei_block),
idx_pblock(path[i].p_idx),
newblock);
/*memmove(++fidx, path[i].p_idx++,
sizeof(struct ext4_extent_idx));
neh->eh_entries++;
BUG_ON(neh->eh_entries > neh->eh_max);*/
path[i].p_idx++;
m++;
}
if (m) {
memmove(++fidx, path[i].p_idx - m,
sizeof(struct ext4_extent_idx) * m);
neh->eh_entries =
cpu_to_le16(le16_to_cpu(neh->eh_entries) + m);
}
set_buffer_uptodate(bh);
unlock_buffer(bh);
err = ext4_journal_dirty_metadata(handle, bh);
if (err)
goto cleanup;
brelse(bh);
bh = NULL;
/* correct old index */
if (m) {
err = ext4_ext_get_access(handle, inode, path + i);
if (err)
goto cleanup;
path[i].p_hdr->eh_entries = cpu_to_le16(le16_to_cpu(path[i].p_hdr->eh_entries)-m);
err = ext4_ext_dirty(handle, inode, path + i);
if (err)
goto cleanup;
}
i--;
}
/* insert new index */
err = ext4_ext_insert_index(handle, inode, path + at,
le32_to_cpu(border), newblock);
cleanup:
if (bh) {
if (buffer_locked(bh))
unlock_buffer(bh);
brelse(bh);
}
if (err) {
/* free all allocated blocks in error case */
for (i = 0; i < depth; i++) {
if (!ablocks[i])
continue;
ext4_free_blocks(handle, inode, ablocks[i], 1);
}
}
kfree(ablocks);
return err;
}
/*
* ext4_ext_grow_indepth:
* implements tree growing procedure:
* - allocates new block
* - moves top-level data (index block or leaf) into the new block
* - initializes new top-level, creating index that points to the
* just created block
*/
static int ext4_ext_grow_indepth(handle_t *handle, struct inode *inode,
struct ext4_ext_path *path,
struct ext4_extent *newext)
{
struct ext4_ext_path *curp = path;
struct ext4_extent_header *neh;
struct ext4_extent_idx *fidx;
struct buffer_head *bh;
ext4_fsblk_t newblock;
int err = 0;
newblock = ext4_ext_new_block(handle, inode, path, newext, &err);
if (newblock == 0)
return err;
bh = sb_getblk(inode->i_sb, newblock);
if (!bh) {
err = -EIO;
ext4_std_error(inode->i_sb, err);
return err;
}
lock_buffer(bh);
err = ext4_journal_get_create_access(handle, bh);
if (err) {
unlock_buffer(bh);
goto out;
}
/* move top-level index/leaf into new block */
memmove(bh->b_data, curp->p_hdr, sizeof(EXT4_I(inode)->i_data));
/* set size of new block */
neh = ext_block_hdr(bh);
/* old root could have indexes or leaves
* so calculate e_max right way */
if (ext_depth(inode))
neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode));
else
neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode));
neh->eh_magic = EXT4_EXT_MAGIC;
set_buffer_uptodate(bh);
unlock_buffer(bh);
err = ext4_journal_dirty_metadata(handle, bh);
if (err)
goto out;
/* create index in new top-level index: num,max,pointer */
err = ext4_ext_get_access(handle, inode, curp);
if (err)
goto out;
curp->p_hdr->eh_magic = EXT4_EXT_MAGIC;
curp->p_hdr->eh_max = cpu_to_le16(ext4_ext_space_root_idx(inode));
curp->p_hdr->eh_entries = cpu_to_le16(1);
curp->p_idx = EXT_FIRST_INDEX(curp->p_hdr);
if (path[0].p_hdr->eh_depth)
curp->p_idx->ei_block =
EXT_FIRST_INDEX(path[0].p_hdr)->ei_block;
else
curp->p_idx->ei_block =
EXT_FIRST_EXTENT(path[0].p_hdr)->ee_block;
ext4_idx_store_pblock(curp->p_idx, newblock);
neh = ext_inode_hdr(inode);
fidx = EXT_FIRST_INDEX(neh);
ext_debug("new root: num %d(%d), lblock %d, ptr %llu\n",
le16_to_cpu(neh->eh_entries), le16_to_cpu(neh->eh_max),
le32_to_cpu(fidx->ei_block), idx_pblock(fidx));
neh->eh_depth = cpu_to_le16(path->p_depth + 1);
err = ext4_ext_dirty(handle, inode, curp);
out:
brelse(bh);
return err;
}
/*
* ext4_ext_create_new_leaf:
* finds empty index and adds new leaf.
* if no free index is found, then it requests in-depth growing.
*/
static int ext4_ext_create_new_leaf(handle_t *handle, struct inode *inode,
struct ext4_ext_path *path,
struct ext4_extent *newext)
{
struct ext4_ext_path *curp;
int depth, i, err = 0;
repeat:
i = depth = ext_depth(inode);
/* walk up to the tree and look for free index entry */
curp = path + depth;
while (i > 0 && !EXT_HAS_FREE_INDEX(curp)) {
i--;
curp--;
}
/* we use already allocated block for index block,
* so subsequent data blocks should be contiguous */
if (EXT_HAS_FREE_INDEX(curp)) {
/* if we found index with free entry, then use that
* entry: create all needed subtree and add new leaf */
err = ext4_ext_split(handle, inode, path, newext, i);
/* refill path */
ext4_ext_drop_refs(path);
path = ext4_ext_find_extent(inode,
(ext4_lblk_t)le32_to_cpu(newext->ee_block),
path);
if (IS_ERR(path))
err = PTR_ERR(path);
} else {
/* tree is full, time to grow in depth */
err = ext4_ext_grow_indepth(handle, inode, path, newext);
if (err)
goto out;
/* refill path */
ext4_ext_drop_refs(path);
path = ext4_ext_find_extent(inode,
(ext4_lblk_t)le32_to_cpu(newext->ee_block),
path);
if (IS_ERR(path)) {
err = PTR_ERR(path);
goto out;
}
/*
* only first (depth 0 -> 1) produces free space;
* in all other cases we have to split the grown tree
*/
depth = ext_depth(inode);
if (path[depth].p_hdr->eh_entries == path[depth].p_hdr->eh_max) {
/* now we need to split */
goto repeat;
}
}
out:
return err;
}
/*
* ext4_ext_next_allocated_block:
* returns allocated block in subsequent extent or EXT_MAX_BLOCK.
* NOTE: it considers block number from index entry as
* allocated block. Thus, index entries have to be consistent
* with leaves.
*/
static ext4_lblk_t
ext4_ext_next_allocated_block(struct ext4_ext_path *path)
{
int depth;
BUG_ON(path == NULL);
depth = path->p_depth;
if (depth == 0 && path->p_ext == NULL)
return EXT_MAX_BLOCK;
while (depth >= 0) {
if (depth == path->p_depth) {
/* leaf */
if (path[depth].p_ext !=
EXT_LAST_EXTENT(path[depth].p_hdr))
return le32_to_cpu(path[depth].p_ext[1].ee_block);
} else {
/* index */
if (path[depth].p_idx !=
EXT_LAST_INDEX(path[depth].p_hdr))
return le32_to_cpu(path[depth].p_idx[1].ei_block);
}
depth--;
}
return EXT_MAX_BLOCK;
}
/*
* ext4_ext_next_leaf_block:
* returns first allocated block from next leaf or EXT_MAX_BLOCK
*/
static ext4_lblk_t ext4_ext_next_leaf_block(struct inode *inode,
struct ext4_ext_path *path)
{
int depth;
BUG_ON(path == NULL);
depth = path->p_depth;
/* zero-tree has no leaf blocks at all */
if (depth == 0)
return EXT_MAX_BLOCK;
/* go to index block */
depth--;
while (depth >= 0) {
if (path[depth].p_idx !=
EXT_LAST_INDEX(path[depth].p_hdr))
return (ext4_lblk_t)
le32_to_cpu(path[depth].p_idx[1].ei_block);
depth--;
}
return EXT_MAX_BLOCK;
}
/*
* ext4_ext_correct_indexes:
* if leaf gets modified and modified extent is first in the leaf,
* then we have to correct all indexes above.
* TODO: do we need to correct tree in all cases?
*/
static int ext4_ext_correct_indexes(handle_t *handle, struct inode *inode,
struct ext4_ext_path *path)
{
struct ext4_extent_header *eh;
int depth = ext_depth(inode);
struct ext4_extent *ex;
__le32 border;
int k, err = 0;
eh = path[depth].p_hdr;
ex = path[depth].p_ext;
BUG_ON(ex == NULL);
BUG_ON(eh == NULL);
if (depth == 0) {
/* there is no tree at all */
return 0;
}
if (ex != EXT_FIRST_EXTENT(eh)) {
/* we correct tree if first leaf got modified only */
return 0;
}
/*
* TODO: we need correction if border is smaller than current one
*/
k = depth - 1;
border = path[depth].p_ext->ee_block;
err = ext4_ext_get_access(handle, inode, path + k);
if (err)
return err;
path[k].p_idx->ei_block = border;
err = ext4_ext_dirty(handle, inode, path + k);
if (err)
return err;
while (k--) {
/* change all left-side indexes */
if (path[k+1].p_idx != EXT_FIRST_INDEX(path[k+1].p_hdr))
break;
err = ext4_ext_get_access(handle, inode, path + k);
if (err)
break;
path[k].p_idx->ei_block = border;
err = ext4_ext_dirty(handle, inode, path + k);
if (err)
break;
}
return err;
}
static int
ext4_can_extents_be_merged(struct inode *inode, struct ext4_extent *ex1,
struct ext4_extent *ex2)
{
unsigned short ext1_ee_len, ext2_ee_len, max_len;
/*
* Make sure that either both extents are uninitialized, or
* both are _not_.
*/
if (ext4_ext_is_uninitialized(ex1) ^ ext4_ext_is_uninitialized(ex2))
return 0;
if (ext4_ext_is_uninitialized(ex1))
max_len = EXT_UNINIT_MAX_LEN;
else
max_len = EXT_INIT_MAX_LEN;
ext1_ee_len = ext4_ext_get_actual_len(ex1);
ext2_ee_len = ext4_ext_get_actual_len(ex2);
if (le32_to_cpu(ex1->ee_block) + ext1_ee_len !=
le32_to_cpu(ex2->ee_block))
return 0;
/*
* To allow future support for preallocated extents to be added
* as an RO_COMPAT feature, refuse to merge to extents if
* this can result in the top bit of ee_len being set.
*/
if (ext1_ee_len + ext2_ee_len > max_len)
return 0;
#ifdef AGGRESSIVE_TEST
if (le16_to_cpu(ex1->ee_len) >= 4)
return 0;
#endif
if (ext_pblock(ex1) + ext1_ee_len == ext_pblock(ex2))
return 1;
return 0;
}
/*
* This function tries to merge the "ex" extent to the next extent in the tree.
* It always tries to merge towards right. If you want to merge towards
* left, pass "ex - 1" as argument instead of "ex".
* Returns 0 if the extents (ex and ex+1) were _not_ merged and returns
* 1 if they got merged.
*/
int ext4_ext_try_to_merge(struct inode *inode,
struct ext4_ext_path *path,
struct ext4_extent *ex)
{
struct ext4_extent_header *eh;
unsigned int depth, len;
int merge_done = 0;
int uninitialized = 0;
depth = ext_depth(inode);
BUG_ON(path[depth].p_hdr == NULL);
eh = path[depth].p_hdr;
while (ex < EXT_LAST_EXTENT(eh)) {
if (!ext4_can_extents_be_merged(inode, ex, ex + 1))
break;
/* merge with next extent! */
if (ext4_ext_is_uninitialized(ex))
uninitialized = 1;
ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
+ ext4_ext_get_actual_len(ex + 1));
if (uninitialized)
ext4_ext_mark_uninitialized(ex);
if (ex + 1 < EXT_LAST_EXTENT(eh)) {
len = (EXT_LAST_EXTENT(eh) - ex - 1)
* sizeof(struct ext4_extent);
memmove(ex + 1, ex + 2, len);
}
eh->eh_entries = cpu_to_le16(le16_to_cpu(eh->eh_entries) - 1);
merge_done = 1;
WARN_ON(eh->eh_entries == 0);
if (!eh->eh_entries)
ext4_error(inode->i_sb, "ext4_ext_try_to_merge",
"inode#%lu, eh->eh_entries = 0!", inode->i_ino);
}
return merge_done;
}
/*
* check if a portion of the "newext" extent overlaps with an
* existing extent.
*
* If there is an overlap discovered, it updates the length of the newext
* such that there will be no overlap, and then returns 1.
* If there is no overlap found, it returns 0.
*/
unsigned int ext4_ext_check_overlap(struct inode *inode,
struct ext4_extent *newext,
struct ext4_ext_path *path)
{
ext4_lblk_t b1, b2;
unsigned int depth, len1;
unsigned int ret = 0;
b1 = le32_to_cpu(newext->ee_block);
len1 = ext4_ext_get_actual_len(newext);
depth = ext_depth(inode);
if (!path[depth].p_ext)
goto out;
b2 = le32_to_cpu(path[depth].p_ext->ee_block);
/*
* get the next allocated block if the extent in the path
* is before the requested block(s)
*/
if (b2 < b1) {
b2 = ext4_ext_next_allocated_block(path);
if (b2 == EXT_MAX_BLOCK)
goto out;
}
/* check for wrap through zero on extent logical start block*/
if (b1 + len1 < b1) {
len1 = EXT_MAX_BLOCK - b1;
newext->ee_len = cpu_to_le16(len1);
ret = 1;
}
/* check for overlap */
if (b1 + len1 > b2) {
newext->ee_len = cpu_to_le16(b2 - b1);
ret = 1;
}
out:
return ret;
}
/*
* ext4_ext_insert_extent:
* tries to merge requsted extent into the existing extent or
* inserts requested extent as new one into the tree,
* creating new leaf in the no-space case.
*/
int ext4_ext_insert_extent(handle_t *handle, struct inode *inode,
struct ext4_ext_path *path,
struct ext4_extent *newext)
{
struct ext4_extent_header * eh;
struct ext4_extent *ex, *fex;
struct ext4_extent *nearex; /* nearest extent */
struct ext4_ext_path *npath = NULL;
int depth, len, err;
ext4_lblk_t next;
unsigned uninitialized = 0;
BUG_ON(ext4_ext_get_actual_len(newext) == 0);
depth = ext_depth(inode);
ex = path[depth].p_ext;
BUG_ON(path[depth].p_hdr == NULL);
/* try to insert block into found extent and return */
if (ex && ext4_can_extents_be_merged(inode, ex, newext)) {
ext_debug("append %d block to %d:%d (from %llu)\n",
ext4_ext_get_actual_len(newext),
le32_to_cpu(ex->ee_block),
ext4_ext_get_actual_len(ex), ext_pblock(ex));
err = ext4_ext_get_access(handle, inode, path + depth);
if (err)
return err;
/*
* ext4_can_extents_be_merged should have checked that either
* both extents are uninitialized, or both aren't. Thus we
* need to check only one of them here.
*/
if (ext4_ext_is_uninitialized(ex))
uninitialized = 1;
ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
+ ext4_ext_get_actual_len(newext));
if (uninitialized)
ext4_ext_mark_uninitialized(ex);
eh = path[depth].p_hdr;
nearex = ex;
goto merge;
}
repeat:
depth = ext_depth(inode);
eh = path[depth].p_hdr;
if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max))
goto has_space;
/* probably next leaf has space for us? */
fex = EXT_LAST_EXTENT(eh);
next = ext4_ext_next_leaf_block(inode, path);
if (le32_to_cpu(newext->ee_block) > le32_to_cpu(fex->ee_block)
&& next != EXT_MAX_BLOCK) {
ext_debug("next leaf block - %d\n", next);
BUG_ON(npath != NULL);
npath = ext4_ext_find_extent(inode, next, NULL);
if (IS_ERR(npath))
return PTR_ERR(npath);
BUG_ON(npath->p_depth != path->p_depth);
eh = npath[depth].p_hdr;
if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max)) {
ext_debug("next leaf isnt full(%d)\n",
le16_to_cpu(eh->eh_entries));
path = npath;
goto repeat;
}
ext_debug("next leaf has no free space(%d,%d)\n",
le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
}
/*
* There is no free space in the found leaf.
* We're gonna add a new leaf in the tree.
*/
err = ext4_ext_create_new_leaf(handle, inode, path, newext);
if (err)
goto cleanup;
depth = ext_depth(inode);
eh = path[depth].p_hdr;
has_space:
nearex = path[depth].p_ext;
err = ext4_ext_get_access(handle, inode, path + depth);
if (err)
goto cleanup;
if (!nearex) {
/* there is no extent in this leaf, create first one */
ext_debug("first extent in the leaf: %d:%llu:%d\n",
le32_to_cpu(newext->ee_block),
ext_pblock(newext),
ext4_ext_get_actual_len(newext));
path[depth].p_ext = EXT_FIRST_EXTENT(eh);
} else if (le32_to_cpu(newext->ee_block)
> le32_to_cpu(nearex->ee_block)) {
/* BUG_ON(newext->ee_block == nearex->ee_block); */
if (nearex != EXT_LAST_EXTENT(eh)) {
len = EXT_MAX_EXTENT(eh) - nearex;
len = (len - 1) * sizeof(struct ext4_extent);
len = len < 0 ? 0 : len;
ext_debug("insert %d:%llu:%d after: nearest 0x%p, "
"move %d from 0x%p to 0x%p\n",
le32_to_cpu(newext->ee_block),
ext_pblock(newext),
ext4_ext_get_actual_len(newext),
nearex, len, nearex + 1, nearex + 2);
memmove(nearex + 2, nearex + 1, len);
}
path[depth].p_ext = nearex + 1;
} else {
BUG_ON(newext->ee_block == nearex->ee_block);
len = (EXT_MAX_EXTENT(eh) - nearex) * sizeof(struct ext4_extent);
len = len < 0 ? 0 : len;
ext_debug("insert %d:%llu:%d before: nearest 0x%p, "
"move %d from 0x%p to 0x%p\n",
le32_to_cpu(newext->ee_block),
ext_pblock(newext),
ext4_ext_get_actual_len(newext),
nearex, len, nearex + 1, nearex + 2);
memmove(nearex + 1, nearex, len);
path[depth].p_ext = nearex;
}
eh->eh_entries = cpu_to_le16(le16_to_cpu(eh->eh_entries)+1);
nearex = path[depth].p_ext;
nearex->ee_block = newext->ee_block;
ext4_ext_store_pblock(nearex, ext_pblock(newext));
nearex->ee_len = newext->ee_len;
merge:
/* try to merge extents to the right */
ext4_ext_try_to_merge(inode, path, nearex);
/* try to merge extents to the left */
/* time to correct all indexes above */
err = ext4_ext_correct_indexes(handle, inode, path);
if (err)
goto cleanup;
err = ext4_ext_dirty(handle, inode, path + depth);
cleanup:
if (npath) {
ext4_ext_drop_refs(npath);
kfree(npath);
}
ext4_ext_tree_changed(inode);
ext4_ext_invalidate_cache(inode);
return err;
}
static void
ext4_ext_put_in_cache(struct inode *inode, ext4_lblk_t block,
__u32 len, ext4_fsblk_t start, int type)
{
struct ext4_ext_cache *cex;
BUG_ON(len == 0);
cex = &EXT4_I(inode)->i_cached_extent;
cex->ec_type = type;
cex->ec_block = block;
cex->ec_len = len;
cex->ec_start = start;
}
/*
* ext4_ext_put_gap_in_cache:
* calculate boundaries of the gap that the requested block fits into
* and cache this gap
*/
static void
ext4_ext_put_gap_in_cache(struct inode *inode, struct ext4_ext_path *path,
ext4_lblk_t block)
{
int depth = ext_depth(inode);
unsigned long len;
ext4_lblk_t lblock;
struct ext4_extent *ex;
ex = path[depth].p_ext;
if (ex == NULL) {
/* there is no extent yet, so gap is [0;-] */
lblock = 0;
len = EXT_MAX_BLOCK;
ext_debug("cache gap(whole file):");
} else if (block < le32_to_cpu(ex->ee_block)) {
lblock = block;
len = le32_to_cpu(ex->ee_block) - block;
ext_debug("cache gap(before): %u [%u:%u]",
block,
le32_to_cpu(ex->ee_block),
ext4_ext_get_actual_len(ex));
} else if (block >= le32_to_cpu(ex->ee_block)
+ ext4_ext_get_actual_len(ex)) {
ext4_lblk_t next;
lblock = le32_to_cpu(ex->ee_block)
+ ext4_ext_get_actual_len(ex);
next = ext4_ext_next_allocated_block(path);
ext_debug("cache gap(after): [%u:%u] %u",
le32_to_cpu(ex->ee_block),
ext4_ext_get_actual_len(ex),
block);
BUG_ON(next == lblock);
len = next - lblock;
} else {
lblock = len = 0;
BUG();
}
ext_debug(" -> %u:%lu\n", lblock, len);
ext4_ext_put_in_cache(inode, lblock, len, 0, EXT4_EXT_CACHE_GAP);
}
static int
ext4_ext_in_cache(struct inode *inode, ext4_lblk_t block,
struct ext4_extent *ex)
{
struct ext4_ext_cache *cex;
cex = &EXT4_I(inode)->i_cached_extent;
/* has cache valid data? */
if (cex->ec_type == EXT4_EXT_CACHE_NO)
return EXT4_EXT_CACHE_NO;
BUG_ON(cex->ec_type != EXT4_EXT_CACHE_GAP &&
cex->ec_type != EXT4_EXT_CACHE_EXTENT);
if (block >= cex->ec_block && block < cex->ec_block + cex->ec_len) {
ex->ee_block = cpu_to_le32(cex->ec_block);
ext4_ext_store_pblock(ex, cex->ec_start);
ex->ee_len = cpu_to_le16(cex->ec_len);
ext_debug("%u cached by %u:%u:%llu\n",
block,
cex->ec_block, cex->ec_len, cex->ec_start);
return cex->ec_type;
}
/* not in cache */
return EXT4_EXT_CACHE_NO;
}
/*
* ext4_ext_rm_idx:
* removes index from the index block.
* It's used in truncate case only, thus all requests are for
* last index in the block only.
*/
static int ext4_ext_rm_idx(handle_t *handle, struct inode *inode,
struct ext4_ext_path *path)
{
struct buffer_head *bh;
int err;
ext4_fsblk_t leaf;
/* free index block */
path--;
leaf = idx_pblock(path->p_idx);
BUG_ON(path->p_hdr->eh_entries == 0);
err = ext4_ext_get_access(handle, inode, path);
if (err)
return err;
path->p_hdr->eh_entries = cpu_to_le16(le16_to_cpu(path->p_hdr->eh_entries)-1);
err = ext4_ext_dirty(handle, inode, path);
if (err)
return err;
ext_debug("index is empty, remove it, free block %llu\n", leaf);
bh = sb_find_get_block(inode->i_sb, leaf);
ext4_forget(handle, 1, inode, bh, leaf);
ext4_free_blocks(handle, inode, leaf, 1);
return err;
}
/*
* ext4_ext_calc_credits_for_insert:
* This routine returns max. credits that the extent tree can consume.
* It should be OK for low-performance paths like ->writepage()
* To allow many writing processes to fit into a single transaction,
* the caller should calculate credits under i_data_sem and
* pass the actual path.
*/
int ext4_ext_calc_credits_for_insert(struct inode *inode,
struct ext4_ext_path *path)
{
int depth, needed;
if (path) {
/* probably there is space in leaf? */
depth = ext_depth(inode);
if (le16_to_cpu(path[depth].p_hdr->eh_entries)
< le16_to_cpu(path[depth].p_hdr->eh_max))
return 1;
}
/*
* given 32-bit logical block (4294967296 blocks), max. tree
* can be 4 levels in depth -- 4 * 340^4 == 53453440000.
* Let's also add one more level for imbalance.
*/
depth = 5;
/* allocation of new data block(s) */
needed = 2;
/*
* tree can be full, so it would need to grow in depth:
* we need one credit to modify old root, credits for
* new root will be added in split accounting
*/
needed += 1;
/*
* Index split can happen, we would need:
* allocate intermediate indexes (bitmap + group)
* + change two blocks at each level, but root (already included)
*/
needed += (depth * 2) + (depth * 2);
/* any allocation modifies superblock */
needed += 1;
return needed;
}
static int ext4_remove_blocks(handle_t *handle, struct inode *inode,
struct ext4_extent *ex,
ext4_lblk_t from, ext4_lblk_t to)
{
struct buffer_head *bh;
unsigned short ee_len = ext4_ext_get_actual_len(ex);
int i;
#ifdef EXTENTS_STATS
{
struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
spin_lock(&sbi->s_ext_stats_lock);
sbi->s_ext_blocks += ee_len;
sbi->s_ext_extents++;
if (ee_len < sbi->s_ext_min)
sbi->s_ext_min = ee_len;
if (ee_len > sbi->s_ext_max)
sbi->s_ext_max = ee_len;
if (ext_depth(inode) > sbi->s_depth_max)
sbi->s_depth_max = ext_depth(inode);
spin_unlock(&sbi->s_ext_stats_lock);
}
#endif
if (from >= le32_to_cpu(ex->ee_block)
&& to == le32_to_cpu(ex->ee_block) + ee_len - 1) {
/* tail removal */
ext4_lblk_t num;
ext4_fsblk_t start;
num = le32_to_cpu(ex->ee_block) + ee_len - from;
start = ext_pblock(ex) + ee_len - num;
ext_debug("free last %u blocks starting %llu\n", num, start);
for (i = 0; i < num; i++) {
bh = sb_find_get_block(inode->i_sb, start + i);
ext4_forget(handle, 0, inode, bh, start + i);
}
ext4_free_blocks(handle, inode, start, num);
} else if (from == le32_to_cpu(ex->ee_block)
&& to <= le32_to_cpu(ex->ee_block) + ee_len - 1) {
printk(KERN_INFO "strange request: removal %u-%u from %u:%u\n",
from, to, le32_to_cpu(ex->ee_block), ee_len);
} else {
printk(KERN_INFO "strange request: removal(2) "
"%u-%u from %u:%u\n",
from, to, le32_to_cpu(ex->ee_block), ee_len);
}
return 0;
}
static int
ext4_ext_rm_leaf(handle_t *handle, struct inode *inode,
struct ext4_ext_path *path, ext4_lblk_t start)
{
int err = 0, correct_index = 0;
int depth = ext_depth(inode), credits;
struct ext4_extent_header *eh;
ext4_lblk_t a, b, block;
unsigned num;
ext4_lblk_t ex_ee_block;
unsigned short ex_ee_len;
unsigned uninitialized = 0;
struct ext4_extent *ex;
/* the header must be checked already in ext4_ext_remove_space() */
ext_debug("truncate since %u in leaf\n", start);
if (!path[depth].p_hdr)
path[depth].p_hdr = ext_block_hdr(path[depth].p_bh);
eh = path[depth].p_hdr;
BUG_ON(eh == NULL);
/* find where to start removing */
ex = EXT_LAST_EXTENT(eh);
ex_ee_block = le32_to_cpu(ex->ee_block);
if (ext4_ext_is_uninitialized(ex))
uninitialized = 1;
ex_ee_len = ext4_ext_get_actual_len(ex);
while (ex >= EXT_FIRST_EXTENT(eh) &&
ex_ee_block + ex_ee_len > start) {
ext_debug("remove ext %lu:%u\n", ex_ee_block, ex_ee_len);
path[depth].p_ext = ex;
a = ex_ee_block > start ? ex_ee_block : start;
b = ex_ee_block + ex_ee_len - 1 < EXT_MAX_BLOCK ?
ex_ee_block + ex_ee_len - 1 : EXT_MAX_BLOCK;
ext_debug(" border %u:%u\n", a, b);
if (a != ex_ee_block && b != ex_ee_block + ex_ee_len - 1) {
block = 0;
num = 0;
BUG();
} else if (a != ex_ee_block) {
/* remove tail of the extent */
block = ex_ee_block;
num = a - block;
} else if (b != ex_ee_block + ex_ee_len - 1) {
/* remove head of the extent */
block = a;
num = b - a;
/* there is no "make a hole" API yet */
BUG();
} else {
/* remove whole extent: excellent! */
block = ex_ee_block;
num = 0;
BUG_ON(a != ex_ee_block);
BUG_ON(b != ex_ee_block + ex_ee_len - 1);
}
/* at present, extent can't cross block group: */
/* leaf + bitmap + group desc + sb + inode */
credits = 5;
if (ex == EXT_FIRST_EXTENT(eh)) {
correct_index = 1;
credits += (ext_depth(inode)) + 1;
}
#ifdef CONFIG_QUOTA
credits += 2 * EXT4_QUOTA_TRANS_BLOCKS(inode->i_sb);
#endif
handle = ext4_ext_journal_restart(handle, credits);
if (IS_ERR(handle)) {
err = PTR_ERR(handle);
goto out;
}
err = ext4_ext_get_access(handle, inode, path + depth);
if (err)
goto out;
err = ext4_remove_blocks(handle, inode, ex, a, b);
if (err)
goto out;
if (num == 0) {
/* this extent is removed; mark slot entirely unused */
ext4_ext_store_pblock(ex, 0);
eh->eh_entries = cpu_to_le16(le16_to_cpu(eh->eh_entries)-1);
}
ex->ee_block = cpu_to_le32(block);
ex->ee_len = cpu_to_le16(num);
/*
* Do not mark uninitialized if all the blocks in the
* extent have been removed.
*/
if (uninitialized && num)
ext4_ext_mark_uninitialized(ex);
err = ext4_ext_dirty(handle, inode, path + depth);
if (err)
goto out;
ext_debug("new extent: %u:%u:%llu\n", block, num,
ext_pblock(ex));
ex--;
ex_ee_block = le32_to_cpu(ex->ee_block);
ex_ee_len = ext4_ext_get_actual_len(ex);
}
if (correct_index && eh->eh_entries)
err = ext4_ext_correct_indexes(handle, inode, path);
/* if this leaf is free, then we should
* remove it from index block above */
if (err == 0 && eh->eh_entries == 0 && path[depth].p_bh != NULL)
err = ext4_ext_rm_idx(handle, inode, path + depth);
out:
return err;
}
/*
* ext4_ext_more_to_rm:
* returns 1 if current index has to be freed (even partial)
*/
static int
ext4_ext_more_to_rm(struct ext4_ext_path *path)
{
BUG_ON(path->p_idx == NULL);
if (path->p_idx < EXT_FIRST_INDEX(path->p_hdr))
return 0;
/*
* if truncate on deeper level happened, it wasn't partial,
* so we have to consider current index for truncation
*/
if (le16_to_cpu(path->p_hdr->eh_entries) == path->p_block)
return 0;
return 1;
}
static int ext4_ext_remove_space(struct inode *inode, ext4_lblk_t start)
{
struct super_block *sb = inode->i_sb;
int depth = ext_depth(inode);
struct ext4_ext_path *path;
handle_t *handle;
int i = 0, err = 0;
ext_debug("truncate since %u\n", start);
/* probably first extent we're gonna free will be last in block */
handle = ext4_journal_start(inode, depth + 1);
if (IS_ERR(handle))
return PTR_ERR(handle);
ext4_ext_invalidate_cache(inode);
/*
* We start scanning from right side, freeing all the blocks
* after i_size and walking into the tree depth-wise.
*/
path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 1), GFP_KERNEL);
if (path == NULL) {
ext4_journal_stop(handle);
return -ENOMEM;
}
path[0].p_hdr = ext_inode_hdr(inode);
if (ext4_ext_check_header(inode, path[0].p_hdr, depth)) {
err = -EIO;
goto out;
}
path[0].p_depth = depth;
while (i >= 0 && err == 0) {
if (i == depth) {
/* this is leaf block */
err = ext4_ext_rm_leaf(handle, inode, path, start);
/* root level has p_bh == NULL, brelse() eats this */
brelse(path[i].p_bh);
path[i].p_bh = NULL;
i--;
continue;
}
/* this is index block */
if (!path[i].p_hdr) {
ext_debug("initialize header\n");
path[i].p_hdr = ext_block_hdr(path[i].p_bh);
}
if (!path[i].p_idx) {
/* this level hasn't been touched yet */
path[i].p_idx = EXT_LAST_INDEX(path[i].p_hdr);
path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries)+1;
ext_debug("init index ptr: hdr 0x%p, num %d\n",
path[i].p_hdr,
le16_to_cpu(path[i].p_hdr->eh_entries));
} else {
/* we were already here, see at next index */
path[i].p_idx--;
}
ext_debug("level %d - index, first 0x%p, cur 0x%p\n",
i, EXT_FIRST_INDEX(path[i].p_hdr),
path[i].p_idx);
if (ext4_ext_more_to_rm(path + i)) {
struct buffer_head *bh;
/* go to the next level */
ext_debug("move to level %d (block %llu)\n",
i + 1, idx_pblock(path[i].p_idx));
memset(path + i + 1, 0, sizeof(*path));
bh = sb_bread(sb, idx_pblock(path[i].p_idx));
if (!bh) {
/* should we reset i_size? */
err = -EIO;
break;
}
if (WARN_ON(i + 1 > depth)) {
err = -EIO;
break;
}
if (ext4_ext_check_header(inode, ext_block_hdr(bh),
depth - i - 1)) {
err = -EIO;
break;
}
path[i + 1].p_bh = bh;
/* save actual number of indexes since this
* number is changed at the next iteration */
path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries);
i++;
} else {
/* we finished processing this index, go up */
if (path[i].p_hdr->eh_entries == 0 && i > 0) {
/* index is empty, remove it;
* handle must be already prepared by the
* truncatei_leaf() */
err = ext4_ext_rm_idx(handle, inode, path + i);
}
/* root level has p_bh == NULL, brelse() eats this */
brelse(path[i].p_bh);
path[i].p_bh = NULL;
i--;
ext_debug("return to level %d\n", i);
}
}
/* TODO: flexible tree reduction should be here */
if (path->p_hdr->eh_entries == 0) {
/*
* truncate to zero freed all the tree,
* so we need to correct eh_depth
*/
err = ext4_ext_get_access(handle, inode, path);
if (err == 0) {
ext_inode_hdr(inode)->eh_depth = 0;
ext_inode_hdr(inode)->eh_max =
cpu_to_le16(ext4_ext_space_root(inode));
err = ext4_ext_dirty(handle, inode, path);
}
}
out:
ext4_ext_tree_changed(inode);
ext4_ext_drop_refs(path);
kfree(path);
ext4_journal_stop(handle);
return err;
}
/*
* called at mount time
*/
void ext4_ext_init(struct super_block *sb)
{
/*
* possible initialization would be here
*/
if (test_opt(sb, EXTENTS)) {
printk("EXT4-fs: file extents enabled");
#ifdef AGGRESSIVE_TEST
printk(", aggressive tests");
#endif
#ifdef CHECK_BINSEARCH
printk(", check binsearch");
#endif
#ifdef EXTENTS_STATS
printk(", stats");
#endif
printk("\n");
#ifdef EXTENTS_STATS
spin_lock_init(&EXT4_SB(sb)->s_ext_stats_lock);
EXT4_SB(sb)->s_ext_min = 1 << 30;
EXT4_SB(sb)->s_ext_max = 0;
#endif
}
}
/*
* called at umount time
*/
void ext4_ext_release(struct super_block *sb)
{
if (!test_opt(sb, EXTENTS))
return;
#ifdef EXTENTS_STATS
if (EXT4_SB(sb)->s_ext_blocks && EXT4_SB(sb)->s_ext_extents) {
struct ext4_sb_info *sbi = EXT4_SB(sb);
printk(KERN_ERR "EXT4-fs: %lu blocks in %lu extents (%lu ave)\n",
sbi->s_ext_blocks, sbi->s_ext_extents,
sbi->s_ext_blocks / sbi->s_ext_extents);
printk(KERN_ERR "EXT4-fs: extents: %lu min, %lu max, max depth %lu\n",
sbi->s_ext_min, sbi->s_ext_max, sbi->s_depth_max);
}
#endif
}
/*
* This function is called by ext4_ext_get_blocks() if someone tries to write
* to an uninitialized extent. It may result in splitting the uninitialized
* extent into multiple extents (upto three - one initialized and two
* uninitialized).
* There are three possibilities:
* a> There is no split required: Entire extent should be initialized
* b> Splits in two extents: Write is happening at either end of the extent
* c> Splits in three extents: Somone is writing in middle of the extent
*/
static int ext4_ext_convert_to_initialized(handle_t *handle,
struct inode *inode,
struct ext4_ext_path *path,
ext4_lblk_t iblock,
unsigned long max_blocks)
{
struct ext4_extent *ex, newex;
struct ext4_extent *ex1 = NULL;
struct ext4_extent *ex2 = NULL;
struct ext4_extent *ex3 = NULL;
struct ext4_extent_header *eh;
ext4_lblk_t ee_block;
unsigned int allocated, ee_len, depth;
ext4_fsblk_t newblock;
int err = 0;
int ret = 0;
depth = ext_depth(inode);
eh = path[depth].p_hdr;
ex = path[depth].p_ext;
ee_block = le32_to_cpu(ex->ee_block);
ee_len = ext4_ext_get_actual_len(ex);
allocated = ee_len - (iblock - ee_block);
newblock = iblock - ee_block + ext_pblock(ex);
ex2 = ex;
/* ex1: ee_block to iblock - 1 : uninitialized */
if (iblock > ee_block) {
ex1 = ex;
ex1->ee_len = cpu_to_le16(iblock - ee_block);
ext4_ext_mark_uninitialized(ex1);
ex2 = &newex;
}
/*
* for sanity, update the length of the ex2 extent before
* we insert ex3, if ex1 is NULL. This is to avoid temporary
* overlap of blocks.
*/
if (!ex1 && allocated > max_blocks)
ex2->ee_len = cpu_to_le16(max_blocks);
/* ex3: to ee_block + ee_len : uninitialised */
if (allocated > max_blocks) {
unsigned int newdepth;
ex3 = &newex;
ex3->ee_block = cpu_to_le32(iblock + max_blocks);
ext4_ext_store_pblock(ex3, newblock + max_blocks);
ex3->ee_len = cpu_to_le16(allocated - max_blocks);
ext4_ext_mark_uninitialized(ex3);
err = ext4_ext_insert_extent(handle, inode, path, ex3);
if (err)
goto out;
/*
* The depth, and hence eh & ex might change
* as part of the insert above.
*/
newdepth = ext_depth(inode);
if (newdepth != depth) {
depth = newdepth;
path = ext4_ext_find_extent(inode, iblock, NULL);
if (IS_ERR(path)) {
err = PTR_ERR(path);
path = NULL;
goto out;
}
eh = path[depth].p_hdr;
ex = path[depth].p_ext;
if (ex2 != &newex)
ex2 = ex;
}
allocated = max_blocks;
}
/*
* If there was a change of depth as part of the
* insertion of ex3 above, we need to update the length
* of the ex1 extent again here
*/
if (ex1 && ex1 != ex) {
ex1 = ex;
ex1->ee_len = cpu_to_le16(iblock - ee_block);
ext4_ext_mark_uninitialized(ex1);
ex2 = &newex;
}
/* ex2: iblock to iblock + maxblocks-1 : initialised */
ex2->ee_block = cpu_to_le32(iblock);
ext4_ext_store_pblock(ex2, newblock);
ex2->ee_len = cpu_to_le16(allocated);
if (ex2 != ex)
goto insert;
err = ext4_ext_get_access(handle, inode, path + depth);
if (err)
goto out;
/*
* New (initialized) extent starts from the first block
* in the current extent. i.e., ex2 == ex
* We have to see if it can be merged with the extent
* on the left.
*/
if (ex2 > EXT_FIRST_EXTENT(eh)) {
/*
* To merge left, pass "ex2 - 1" to try_to_merge(),
* since it merges towards right _only_.
*/
ret = ext4_ext_try_to_merge(inode, path, ex2 - 1);
if (ret) {
err = ext4_ext_correct_indexes(handle, inode, path);
if (err)
goto out;
depth = ext_depth(inode);
ex2--;
}
}
/*
* Try to Merge towards right. This might be required
* only when the whole extent is being written to.
* i.e. ex2 == ex and ex3 == NULL.
*/
if (!ex3) {
ret = ext4_ext_try_to_merge(inode, path, ex2);
if (ret) {
err = ext4_ext_correct_indexes(handle, inode, path);
if (err)
goto out;
}
}
/* Mark modified extent as dirty */
err = ext4_ext_dirty(handle, inode, path + depth);
goto out;
insert:
err = ext4_ext_insert_extent(handle, inode, path, &newex);
out:
return err ? err : allocated;
}
/*
* 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_ext_get_blocks(handle_t *handle, struct inode *inode,
ext4_lblk_t iblock,
unsigned long max_blocks, struct buffer_head *bh_result,
int create, int extend_disksize)
{
struct ext4_ext_path *path = NULL;
struct ext4_extent_header *eh;
struct ext4_extent newex, *ex;
ext4_fsblk_t goal, newblock;
int err = 0, depth, ret;
unsigned long allocated = 0;
__clear_bit(BH_New, &bh_result->b_state);
ext_debug("blocks %u/%lu requested for inode %u\n",
iblock, max_blocks, inode->i_ino);
/* check in cache */
goal = ext4_ext_in_cache(inode, iblock, &newex);
if (goal) {
if (goal == EXT4_EXT_CACHE_GAP) {
if (!create) {
/*
* block isn't allocated yet and
* user doesn't want to allocate it
*/
goto out2;
}
/* we should allocate requested block */
} else if (goal == EXT4_EXT_CACHE_EXTENT) {
/* block is already allocated */
newblock = iblock
- le32_to_cpu(newex.ee_block)
+ ext_pblock(&newex);
/* number of remaining blocks in the extent */
allocated = le16_to_cpu(newex.ee_len) -
(iblock - le32_to_cpu(newex.ee_block));
goto out;
} else {
BUG();
}
}
/* find extent for this block */
path = ext4_ext_find_extent(inode, iblock, NULL);
if (IS_ERR(path)) {
err = PTR_ERR(path);
path = NULL;
goto out2;
}
depth = ext_depth(inode);
/*
* consistent leaf must not be empty;
* this situation is possible, though, _during_ tree modification;
* this is why assert can't be put in ext4_ext_find_extent()
*/
BUG_ON(path[depth].p_ext == NULL && depth != 0);
eh = path[depth].p_hdr;
ex = path[depth].p_ext;
if (ex) {
ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block);
ext4_fsblk_t ee_start = ext_pblock(ex);
unsigned short ee_len;
/*
* Uninitialized extents are treated as holes, except that
* we split out initialized portions during a write.
*/
ee_len = ext4_ext_get_actual_len(ex);
/* if found extent covers block, simply return it */
if (iblock >= ee_block && iblock < ee_block + ee_len) {
newblock = iblock - ee_block + ee_start;
/* number of remaining blocks in the extent */
allocated = ee_len - (iblock - ee_block);
ext_debug("%u fit into %lu:%d -> %llu\n", iblock,
ee_block, ee_len, newblock);
/* Do not put uninitialized extent in the cache */
if (!ext4_ext_is_uninitialized(ex)) {
ext4_ext_put_in_cache(inode, ee_block,
ee_len, ee_start,
EXT4_EXT_CACHE_EXTENT);
goto out;
}
if (create == EXT4_CREATE_UNINITIALIZED_EXT)
goto out;
if (!create)
goto out2;
ret = ext4_ext_convert_to_initialized(handle, inode,
path, iblock,
max_blocks);
if (ret <= 0)
goto out2;
else
allocated = ret;
goto outnew;
}
}
/*
* requested block isn't allocated yet;
* we couldn't try to create block if create flag is zero
*/
if (!create) {
/*
* put just found gap into cache to speed up
* subsequent requests
*/
ext4_ext_put_gap_in_cache(inode, path, iblock);
goto out2;
}
/*
* Okay, we need to do block allocation. Lazily initialize the block
* allocation info here if necessary.
*/
if (S_ISREG(inode->i_mode) && (!EXT4_I(inode)->i_block_alloc_info))
ext4_init_block_alloc_info(inode);
/* allocate new block */
goal = ext4_ext_find_goal(inode, path, iblock);
/*
* See if request is beyond maximum number of blocks we can have in
* a single extent. For an initialized extent this limit is
* EXT_INIT_MAX_LEN and for an uninitialized extent this limit is
* EXT_UNINIT_MAX_LEN.
*/
if (max_blocks > EXT_INIT_MAX_LEN &&
create != EXT4_CREATE_UNINITIALIZED_EXT)
max_blocks = EXT_INIT_MAX_LEN;
else if (max_blocks > EXT_UNINIT_MAX_LEN &&
create == EXT4_CREATE_UNINITIALIZED_EXT)
max_blocks = EXT_UNINIT_MAX_LEN;
/* Check if we can really insert (iblock)::(iblock+max_blocks) extent */
newex.ee_block = cpu_to_le32(iblock);
newex.ee_len = cpu_to_le16(max_blocks);
err = ext4_ext_check_overlap(inode, &newex, path);
if (err)
allocated = le16_to_cpu(newex.ee_len);
else
allocated = max_blocks;
newblock = ext4_new_blocks(handle, inode, goal, &allocated, &err);
if (!newblock)
goto out2;
ext_debug("allocate new block: goal %llu, found %llu/%lu\n",
goal, newblock, allocated);
/* try to insert new extent into found leaf and return */
ext4_ext_store_pblock(&newex, newblock);
newex.ee_len = cpu_to_le16(allocated);
if (create == EXT4_CREATE_UNINITIALIZED_EXT) /* Mark uninitialized */
ext4_ext_mark_uninitialized(&newex);
err = ext4_ext_insert_extent(handle, inode, path, &newex);
if (err) {
/* free data blocks we just allocated */
ext4_free_blocks(handle, inode, ext_pblock(&newex),
le16_to_cpu(newex.ee_len));
goto out2;
}
if (extend_disksize && inode->i_size > EXT4_I(inode)->i_disksize)
EXT4_I(inode)->i_disksize = inode->i_size;
/* previous routine could use block we allocated */
newblock = ext_pblock(&newex);
outnew:
__set_bit(BH_New, &bh_result->b_state);
/* Cache only when it is _not_ an uninitialized extent */
if (create != EXT4_CREATE_UNINITIALIZED_EXT)
ext4_ext_put_in_cache(inode, iblock, allocated, newblock,
EXT4_EXT_CACHE_EXTENT);
out:
if (allocated > max_blocks)
allocated = max_blocks;
ext4_ext_show_leaf(inode, path);
__set_bit(BH_Mapped, &bh_result->b_state);
bh_result->b_bdev = inode->i_sb->s_bdev;
bh_result->b_blocknr = newblock;
out2:
if (path) {
ext4_ext_drop_refs(path);
kfree(path);
}
return err ? err : allocated;
}
void ext4_ext_truncate(struct inode * inode, struct page *page)
{
struct address_space *mapping = inode->i_mapping;
struct super_block *sb = inode->i_sb;
ext4_lblk_t last_block;
handle_t *handle;
int err = 0;
/*
* probably first extent we're gonna free will be last in block
*/
err = ext4_writepage_trans_blocks(inode) + 3;
handle = ext4_journal_start(inode, err);
if (IS_ERR(handle)) {
if (page) {
clear_highpage(page);
flush_dcache_page(page);
unlock_page(page);
page_cache_release(page);
}
return;
}
if (page)
ext4_block_truncate_page(handle, page, mapping, inode->i_size);
down_write(&EXT4_I(inode)->i_data_sem);
ext4_ext_invalidate_cache(inode);
/*
* TODO: optimization is possible here.
* Probably we need not scan at all,
* because page truncation is enough.
*/
if (ext4_orphan_add(handle, inode))
goto out_stop;
/* we have to know where to truncate from in crash case */
EXT4_I(inode)->i_disksize = inode->i_size;
ext4_mark_inode_dirty(handle, inode);
last_block = (inode->i_size + sb->s_blocksize - 1)
>> EXT4_BLOCK_SIZE_BITS(sb);
err = ext4_ext_remove_space(inode, last_block);
/* 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);
up_write(&EXT4_I(inode)->i_data_sem);
ext4_journal_stop(handle);
}
/*
* ext4_ext_writepage_trans_blocks:
* calculate max number of blocks we could modify
* in order to allocate new block for an inode
*/
int ext4_ext_writepage_trans_blocks(struct inode *inode, int num)
{
int needed;
needed = ext4_ext_calc_credits_for_insert(inode, NULL);
/* caller wants to allocate num blocks, but note it includes sb */
needed = needed * num - (num - 1);
#ifdef CONFIG_QUOTA
needed += 2 * EXT4_QUOTA_TRANS_BLOCKS(inode->i_sb);
#endif
return needed;
}
/*
* preallocate space for a file. This implements ext4's fallocate inode
* operation, which gets called from sys_fallocate system call.
* For block-mapped files, posix_fallocate should fall back to the method
* of writing zeroes to the required new blocks (the same behavior which is
* expected for file systems which do not support fallocate() system call).
*/
long ext4_fallocate(struct inode *inode, int mode, loff_t offset, loff_t len)
{
handle_t *handle;
ext4_lblk_t block;
unsigned long max_blocks;
ext4_fsblk_t nblocks = 0;
int ret = 0;
int ret2 = 0;
int retries = 0;
struct buffer_head map_bh;
unsigned int credits, blkbits = inode->i_blkbits;
/*
* currently supporting (pre)allocate mode for extent-based
* files _only_
*/
if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL))
return -EOPNOTSUPP;
/* preallocation to directories is currently not supported */
if (S_ISDIR(inode->i_mode))
return -ENODEV;
block = offset >> blkbits;
max_blocks = (EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits)
- block;
/*
* credits to insert 1 extent into extent tree + buffers to be able to
* modify 1 super block, 1 block bitmap and 1 group descriptor.
*/
credits = EXT4_DATA_TRANS_BLOCKS(inode->i_sb) + 3;
down_write((&EXT4_I(inode)->i_data_sem));
retry:
while (ret >= 0 && ret < max_blocks) {
block = block + ret;
max_blocks = max_blocks - ret;
handle = ext4_journal_start(inode, credits);
if (IS_ERR(handle)) {
ret = PTR_ERR(handle);
break;
}
ret = ext4_ext_get_blocks(handle, inode, block,
max_blocks, &map_bh,
EXT4_CREATE_UNINITIALIZED_EXT, 0);
WARN_ON(ret <= 0);
if (ret <= 0) {
ext4_error(inode->i_sb, "ext4_fallocate",
"ext4_ext_get_blocks returned error: "
"inode#%lu, block=%u, max_blocks=%lu",
inode->i_ino, block, max_blocks);
ret = -EIO;
ext4_mark_inode_dirty(handle, inode);
ret2 = ext4_journal_stop(handle);
break;
}
if (ret > 0) {
/* check wrap through sign-bit/zero here */
if ((block + ret) < 0 || (block + ret) < block) {
ret = -EIO;
ext4_mark_inode_dirty(handle, inode);
ret2 = ext4_journal_stop(handle);
break;
}
if (buffer_new(&map_bh) && ((block + ret) >
(EXT4_BLOCK_ALIGN(i_size_read(inode), blkbits)
>> blkbits)))
nblocks = nblocks + ret;
}
/* Update ctime if new blocks get allocated */
if (nblocks) {
struct timespec now;
now = current_fs_time(inode->i_sb);
if (!timespec_equal(&inode->i_ctime, &now))
inode->i_ctime = now;
}
ext4_mark_inode_dirty(handle, inode);
ret2 = ext4_journal_stop(handle);
if (ret2)
break;
}
if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
goto retry;
up_write((&EXT4_I(inode)->i_data_sem));
/*
* Time to update the file size.
* Update only when preallocation was requested beyond the file size.
*/
if (!(mode & FALLOC_FL_KEEP_SIZE) &&
(offset + len) > i_size_read(inode)) {
if (ret > 0) {
/*
* if no error, we assume preallocation succeeded
* completely
*/
mutex_lock(&inode->i_mutex);
i_size_write(inode, offset + len);
EXT4_I(inode)->i_disksize = i_size_read(inode);
mutex_unlock(&inode->i_mutex);
} else if (ret < 0 && nblocks) {
/* Handle partial allocation scenario */
loff_t newsize;
mutex_lock(&inode->i_mutex);
newsize = (nblocks << blkbits) + i_size_read(inode);
i_size_write(inode, EXT4_BLOCK_ALIGN(newsize, blkbits));
EXT4_I(inode)->i_disksize = i_size_read(inode);
mutex_unlock(&inode->i_mutex);
}
}
return ret > 0 ? ret2 : ret;
}
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