OpenCloudOS-Kernel/fs/xfs/xfs_buf.h

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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 2000-2005 Silicon Graphics, Inc.
* All Rights Reserved.
*/
#ifndef __XFS_BUF_H__
#define __XFS_BUF_H__
#include <linux/list.h>
#include <linux/types.h>
#include <linux/spinlock.h>
#include <linux/mm.h>
#include <linux/fs.h>
#include <linux/dax.h>
#include <linux/uio.h>
#include <linux/list_lru.h>
/*
* Base types
*/
#define XFS_BUF_DADDR_NULL ((xfs_daddr_t) (-1LL))
typedef enum {
XBRW_READ = 1, /* transfer into target memory */
XBRW_WRITE = 2, /* transfer from target memory */
XBRW_ZERO = 3, /* Zero target memory */
} xfs_buf_rw_t;
xfs: fix race while discarding buffers [V4] While xfs_buftarg_shrink() is freeing buffers from the dispose list (filled with buffers from lru list), there is a possibility to have xfs_buf_stale() racing with it, and removing buffers from dispose list before xfs_buftarg_shrink() does it. This happens because xfs_buftarg_shrink() handle the dispose list without locking and the test condition in xfs_buf_stale() checks for the buffer being in *any* list: if (!list_empty(&bp->b_lru)) If the buffer happens to be on dispose list, this causes the buffer counter of lru list (btp->bt_lru_nr) to be decremented twice (once in xfs_buftarg_shrink() and another in xfs_buf_stale()) causing a wrong account usage of the lru list. This may cause xfs_buftarg_shrink() to return a wrong value to the memory shrinker shrink_slab(), and such account error may also cause an underflowed value to be returned; since the counter is lower than the current number of items in the lru list, a decrement may happen when the counter is 0, causing an underflow on the counter. The fix uses a new flag field (and a new buffer flag) to serialize buffer handling during the shrink process. The new flag field has been designed to use btp->bt_lru_lock/unlock instead of xfs_buf_lock/unlock mechanism. dchinner, sandeen, aquini and aris also deserve credits for this. Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com> Reviewed-by: Ben Myers <bpm@sgi.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2012-08-11 02:01:51 +08:00
#define XBF_READ (1 << 0) /* buffer intended for reading from device */
#define XBF_WRITE (1 << 1) /* buffer intended for writing to device */
#define XBF_READ_AHEAD (1 << 2) /* asynchronous read-ahead */
#define XBF_NO_IOACCT (1 << 3) /* bypass I/O accounting (non-LRU bufs) */
xfs: fix race while discarding buffers [V4] While xfs_buftarg_shrink() is freeing buffers from the dispose list (filled with buffers from lru list), there is a possibility to have xfs_buf_stale() racing with it, and removing buffers from dispose list before xfs_buftarg_shrink() does it. This happens because xfs_buftarg_shrink() handle the dispose list without locking and the test condition in xfs_buf_stale() checks for the buffer being in *any* list: if (!list_empty(&bp->b_lru)) If the buffer happens to be on dispose list, this causes the buffer counter of lru list (btp->bt_lru_nr) to be decremented twice (once in xfs_buftarg_shrink() and another in xfs_buf_stale()) causing a wrong account usage of the lru list. This may cause xfs_buftarg_shrink() to return a wrong value to the memory shrinker shrink_slab(), and such account error may also cause an underflowed value to be returned; since the counter is lower than the current number of items in the lru list, a decrement may happen when the counter is 0, causing an underflow on the counter. The fix uses a new flag field (and a new buffer flag) to serialize buffer handling during the shrink process. The new flag field has been designed to use btp->bt_lru_lock/unlock instead of xfs_buf_lock/unlock mechanism. dchinner, sandeen, aquini and aris also deserve credits for this. Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com> Reviewed-by: Ben Myers <bpm@sgi.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2012-08-11 02:01:51 +08:00
#define XBF_ASYNC (1 << 4) /* initiator will not wait for completion */
#define XBF_DONE (1 << 5) /* all pages in the buffer uptodate */
#define XBF_STALE (1 << 6) /* buffer has been staled, do not find it */
xfs: abort metadata writeback on permanent errors If we are doing aysnc writeback of metadata, we can get write errors but have nobody to report them to. At the moment, we simply attempt to reissue the write from io completion in the hope that it's a transient error. When it's not a transient error, the buffer is stuck forever in this loop, and we cannot break out of it. Eventually, unmount will hang because the AIL cannot be emptied and everything goes downhill from them. To solve this problem, only retry the write IO once before aborting it. We don't throw the buffer away because some transient errors can last minutes (e.g. FC path failover) or even hours (thin provisioned devices that have run out of backing space) before they go away. Hence we really want to keep trying until we can't try any more. Because the buffer was not cleaned, however, it does not get removed from the AIL and hence the next pass across the AIL will start IO on it again. As such, we still get the "retry forever" semantics that we currently have, but we allow other access to the buffer in the mean time. Meanwhile the filesystem can continue to modify the buffer and relog it, so the IO errors won't hang the log or the filesystem. Now when we are pushing the AIL, we can see all these "permanent IO error" buffers and we can issue a warning about failures before we retry the IO. We can also catch these buffers when unmounting an issue a corruption warning, too. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Ben Myers <bpm@sgi.com>
2013-12-12 13:34:38 +08:00
#define XBF_WRITE_FAIL (1 << 24)/* async writes have failed on this buffer */
/* I/O hints for the BIO layer */
xfs: fix race while discarding buffers [V4] While xfs_buftarg_shrink() is freeing buffers from the dispose list (filled with buffers from lru list), there is a possibility to have xfs_buf_stale() racing with it, and removing buffers from dispose list before xfs_buftarg_shrink() does it. This happens because xfs_buftarg_shrink() handle the dispose list without locking and the test condition in xfs_buf_stale() checks for the buffer being in *any* list: if (!list_empty(&bp->b_lru)) If the buffer happens to be on dispose list, this causes the buffer counter of lru list (btp->bt_lru_nr) to be decremented twice (once in xfs_buftarg_shrink() and another in xfs_buf_stale()) causing a wrong account usage of the lru list. This may cause xfs_buftarg_shrink() to return a wrong value to the memory shrinker shrink_slab(), and such account error may also cause an underflowed value to be returned; since the counter is lower than the current number of items in the lru list, a decrement may happen when the counter is 0, causing an underflow on the counter. The fix uses a new flag field (and a new buffer flag) to serialize buffer handling during the shrink process. The new flag field has been designed to use btp->bt_lru_lock/unlock instead of xfs_buf_lock/unlock mechanism. dchinner, sandeen, aquini and aris also deserve credits for this. Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com> Reviewed-by: Ben Myers <bpm@sgi.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2012-08-11 02:01:51 +08:00
#define XBF_SYNCIO (1 << 10)/* treat this buffer as synchronous I/O */
#define XBF_FUA (1 << 11)/* force cache write through mode */
#define XBF_FLUSH (1 << 12)/* flush the disk cache before a write */
/* flags used only as arguments to access routines */
xfs: fix race while discarding buffers [V4] While xfs_buftarg_shrink() is freeing buffers from the dispose list (filled with buffers from lru list), there is a possibility to have xfs_buf_stale() racing with it, and removing buffers from dispose list before xfs_buftarg_shrink() does it. This happens because xfs_buftarg_shrink() handle the dispose list without locking and the test condition in xfs_buf_stale() checks for the buffer being in *any* list: if (!list_empty(&bp->b_lru)) If the buffer happens to be on dispose list, this causes the buffer counter of lru list (btp->bt_lru_nr) to be decremented twice (once in xfs_buftarg_shrink() and another in xfs_buf_stale()) causing a wrong account usage of the lru list. This may cause xfs_buftarg_shrink() to return a wrong value to the memory shrinker shrink_slab(), and such account error may also cause an underflowed value to be returned; since the counter is lower than the current number of items in the lru list, a decrement may happen when the counter is 0, causing an underflow on the counter. The fix uses a new flag field (and a new buffer flag) to serialize buffer handling during the shrink process. The new flag field has been designed to use btp->bt_lru_lock/unlock instead of xfs_buf_lock/unlock mechanism. dchinner, sandeen, aquini and aris also deserve credits for this. Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com> Reviewed-by: Ben Myers <bpm@sgi.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2012-08-11 02:01:51 +08:00
#define XBF_TRYLOCK (1 << 16)/* lock requested, but do not wait */
#define XBF_UNMAPPED (1 << 17)/* do not map the buffer */
/* flags used only internally */
xfs: fix race while discarding buffers [V4] While xfs_buftarg_shrink() is freeing buffers from the dispose list (filled with buffers from lru list), there is a possibility to have xfs_buf_stale() racing with it, and removing buffers from dispose list before xfs_buftarg_shrink() does it. This happens because xfs_buftarg_shrink() handle the dispose list without locking and the test condition in xfs_buf_stale() checks for the buffer being in *any* list: if (!list_empty(&bp->b_lru)) If the buffer happens to be on dispose list, this causes the buffer counter of lru list (btp->bt_lru_nr) to be decremented twice (once in xfs_buftarg_shrink() and another in xfs_buf_stale()) causing a wrong account usage of the lru list. This may cause xfs_buftarg_shrink() to return a wrong value to the memory shrinker shrink_slab(), and such account error may also cause an underflowed value to be returned; since the counter is lower than the current number of items in the lru list, a decrement may happen when the counter is 0, causing an underflow on the counter. The fix uses a new flag field (and a new buffer flag) to serialize buffer handling during the shrink process. The new flag field has been designed to use btp->bt_lru_lock/unlock instead of xfs_buf_lock/unlock mechanism. dchinner, sandeen, aquini and aris also deserve credits for this. Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com> Reviewed-by: Ben Myers <bpm@sgi.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2012-08-11 02:01:51 +08:00
#define _XBF_PAGES (1 << 20)/* backed by refcounted pages */
#define _XBF_KMEM (1 << 21)/* backed by heap memory */
#define _XBF_DELWRI_Q (1 << 22)/* buffer on a delwri queue */
#define _XBF_COMPOUND (1 << 23)/* compound buffer */
typedef unsigned int xfs_buf_flags_t;
xfs: event tracing support Convert the old xfs tracing support that could only be used with the out of tree kdb and xfsidbg patches to use the generic event tracer. To use it make sure CONFIG_EVENT_TRACING is enabled and then enable all xfs trace channels by: echo 1 > /sys/kernel/debug/tracing/events/xfs/enable or alternatively enable single events by just doing the same in one event subdirectory, e.g. echo 1 > /sys/kernel/debug/tracing/events/xfs/xfs_ihold/enable or set more complex filters, etc. In Documentation/trace/events.txt all this is desctribed in more detail. To reads the events do a cat /sys/kernel/debug/tracing/trace Compared to the last posting this patch converts the tracing mostly to the one tracepoint per callsite model that other users of the new tracing facility also employ. This allows a very fine-grained control of the tracing, a cleaner output of the traces and also enables the perf tool to use each tracepoint as a virtual performance counter, allowing us to e.g. count how often certain workloads git various spots in XFS. Take a look at http://lwn.net/Articles/346470/ for some examples. Also the btree tracing isn't included at all yet, as it will require additional core tracing features not in mainline yet, I plan to deliver it later. And the really nice thing about this patch is that it actually removes many lines of code while adding this nice functionality: fs/xfs/Makefile | 8 fs/xfs/linux-2.6/xfs_acl.c | 1 fs/xfs/linux-2.6/xfs_aops.c | 52 - fs/xfs/linux-2.6/xfs_aops.h | 2 fs/xfs/linux-2.6/xfs_buf.c | 117 +-- fs/xfs/linux-2.6/xfs_buf.h | 33 fs/xfs/linux-2.6/xfs_fs_subr.c | 3 fs/xfs/linux-2.6/xfs_ioctl.c | 1 fs/xfs/linux-2.6/xfs_ioctl32.c | 1 fs/xfs/linux-2.6/xfs_iops.c | 1 fs/xfs/linux-2.6/xfs_linux.h | 1 fs/xfs/linux-2.6/xfs_lrw.c | 87 -- fs/xfs/linux-2.6/xfs_lrw.h | 45 - fs/xfs/linux-2.6/xfs_super.c | 104 --- fs/xfs/linux-2.6/xfs_super.h | 7 fs/xfs/linux-2.6/xfs_sync.c | 1 fs/xfs/linux-2.6/xfs_trace.c | 75 ++ fs/xfs/linux-2.6/xfs_trace.h | 1369 +++++++++++++++++++++++++++++++++++++++++ fs/xfs/linux-2.6/xfs_vnode.h | 4 fs/xfs/quota/xfs_dquot.c | 110 --- fs/xfs/quota/xfs_dquot.h | 21 fs/xfs/quota/xfs_qm.c | 40 - fs/xfs/quota/xfs_qm_syscalls.c | 4 fs/xfs/support/ktrace.c | 323 --------- fs/xfs/support/ktrace.h | 85 -- fs/xfs/xfs.h | 16 fs/xfs/xfs_ag.h | 14 fs/xfs/xfs_alloc.c | 230 +----- fs/xfs/xfs_alloc.h | 27 fs/xfs/xfs_alloc_btree.c | 1 fs/xfs/xfs_attr.c | 107 --- fs/xfs/xfs_attr.h | 10 fs/xfs/xfs_attr_leaf.c | 14 fs/xfs/xfs_attr_sf.h | 40 - fs/xfs/xfs_bmap.c | 507 +++------------ fs/xfs/xfs_bmap.h | 49 - fs/xfs/xfs_bmap_btree.c | 6 fs/xfs/xfs_btree.c | 5 fs/xfs/xfs_btree_trace.h | 17 fs/xfs/xfs_buf_item.c | 87 -- fs/xfs/xfs_buf_item.h | 20 fs/xfs/xfs_da_btree.c | 3 fs/xfs/xfs_da_btree.h | 7 fs/xfs/xfs_dfrag.c | 2 fs/xfs/xfs_dir2.c | 8 fs/xfs/xfs_dir2_block.c | 20 fs/xfs/xfs_dir2_leaf.c | 21 fs/xfs/xfs_dir2_node.c | 27 fs/xfs/xfs_dir2_sf.c | 26 fs/xfs/xfs_dir2_trace.c | 216 ------ fs/xfs/xfs_dir2_trace.h | 72 -- fs/xfs/xfs_filestream.c | 8 fs/xfs/xfs_fsops.c | 2 fs/xfs/xfs_iget.c | 111 --- fs/xfs/xfs_inode.c | 67 -- fs/xfs/xfs_inode.h | 76 -- fs/xfs/xfs_inode_item.c | 5 fs/xfs/xfs_iomap.c | 85 -- fs/xfs/xfs_iomap.h | 8 fs/xfs/xfs_log.c | 181 +---- fs/xfs/xfs_log_priv.h | 20 fs/xfs/xfs_log_recover.c | 1 fs/xfs/xfs_mount.c | 2 fs/xfs/xfs_quota.h | 8 fs/xfs/xfs_rename.c | 1 fs/xfs/xfs_rtalloc.c | 1 fs/xfs/xfs_rw.c | 3 fs/xfs/xfs_trans.h | 47 + fs/xfs/xfs_trans_buf.c | 62 - fs/xfs/xfs_vnodeops.c | 8 70 files changed, 2151 insertions(+), 2592 deletions(-) Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Alex Elder <aelder@sgi.com>
2009-12-15 07:14:59 +08:00
#define XFS_BUF_FLAGS \
{ XBF_READ, "READ" }, \
{ XBF_WRITE, "WRITE" }, \
{ XBF_READ_AHEAD, "READ_AHEAD" }, \
{ XBF_NO_IOACCT, "NO_IOACCT" }, \
xfs: event tracing support Convert the old xfs tracing support that could only be used with the out of tree kdb and xfsidbg patches to use the generic event tracer. To use it make sure CONFIG_EVENT_TRACING is enabled and then enable all xfs trace channels by: echo 1 > /sys/kernel/debug/tracing/events/xfs/enable or alternatively enable single events by just doing the same in one event subdirectory, e.g. echo 1 > /sys/kernel/debug/tracing/events/xfs/xfs_ihold/enable or set more complex filters, etc. In Documentation/trace/events.txt all this is desctribed in more detail. To reads the events do a cat /sys/kernel/debug/tracing/trace Compared to the last posting this patch converts the tracing mostly to the one tracepoint per callsite model that other users of the new tracing facility also employ. This allows a very fine-grained control of the tracing, a cleaner output of the traces and also enables the perf tool to use each tracepoint as a virtual performance counter, allowing us to e.g. count how often certain workloads git various spots in XFS. Take a look at http://lwn.net/Articles/346470/ for some examples. Also the btree tracing isn't included at all yet, as it will require additional core tracing features not in mainline yet, I plan to deliver it later. And the really nice thing about this patch is that it actually removes many lines of code while adding this nice functionality: fs/xfs/Makefile | 8 fs/xfs/linux-2.6/xfs_acl.c | 1 fs/xfs/linux-2.6/xfs_aops.c | 52 - fs/xfs/linux-2.6/xfs_aops.h | 2 fs/xfs/linux-2.6/xfs_buf.c | 117 +-- fs/xfs/linux-2.6/xfs_buf.h | 33 fs/xfs/linux-2.6/xfs_fs_subr.c | 3 fs/xfs/linux-2.6/xfs_ioctl.c | 1 fs/xfs/linux-2.6/xfs_ioctl32.c | 1 fs/xfs/linux-2.6/xfs_iops.c | 1 fs/xfs/linux-2.6/xfs_linux.h | 1 fs/xfs/linux-2.6/xfs_lrw.c | 87 -- fs/xfs/linux-2.6/xfs_lrw.h | 45 - fs/xfs/linux-2.6/xfs_super.c | 104 --- fs/xfs/linux-2.6/xfs_super.h | 7 fs/xfs/linux-2.6/xfs_sync.c | 1 fs/xfs/linux-2.6/xfs_trace.c | 75 ++ fs/xfs/linux-2.6/xfs_trace.h | 1369 +++++++++++++++++++++++++++++++++++++++++ fs/xfs/linux-2.6/xfs_vnode.h | 4 fs/xfs/quota/xfs_dquot.c | 110 --- fs/xfs/quota/xfs_dquot.h | 21 fs/xfs/quota/xfs_qm.c | 40 - fs/xfs/quota/xfs_qm_syscalls.c | 4 fs/xfs/support/ktrace.c | 323 --------- fs/xfs/support/ktrace.h | 85 -- fs/xfs/xfs.h | 16 fs/xfs/xfs_ag.h | 14 fs/xfs/xfs_alloc.c | 230 +----- fs/xfs/xfs_alloc.h | 27 fs/xfs/xfs_alloc_btree.c | 1 fs/xfs/xfs_attr.c | 107 --- fs/xfs/xfs_attr.h | 10 fs/xfs/xfs_attr_leaf.c | 14 fs/xfs/xfs_attr_sf.h | 40 - fs/xfs/xfs_bmap.c | 507 +++------------ fs/xfs/xfs_bmap.h | 49 - fs/xfs/xfs_bmap_btree.c | 6 fs/xfs/xfs_btree.c | 5 fs/xfs/xfs_btree_trace.h | 17 fs/xfs/xfs_buf_item.c | 87 -- fs/xfs/xfs_buf_item.h | 20 fs/xfs/xfs_da_btree.c | 3 fs/xfs/xfs_da_btree.h | 7 fs/xfs/xfs_dfrag.c | 2 fs/xfs/xfs_dir2.c | 8 fs/xfs/xfs_dir2_block.c | 20 fs/xfs/xfs_dir2_leaf.c | 21 fs/xfs/xfs_dir2_node.c | 27 fs/xfs/xfs_dir2_sf.c | 26 fs/xfs/xfs_dir2_trace.c | 216 ------ fs/xfs/xfs_dir2_trace.h | 72 -- fs/xfs/xfs_filestream.c | 8 fs/xfs/xfs_fsops.c | 2 fs/xfs/xfs_iget.c | 111 --- fs/xfs/xfs_inode.c | 67 -- fs/xfs/xfs_inode.h | 76 -- fs/xfs/xfs_inode_item.c | 5 fs/xfs/xfs_iomap.c | 85 -- fs/xfs/xfs_iomap.h | 8 fs/xfs/xfs_log.c | 181 +---- fs/xfs/xfs_log_priv.h | 20 fs/xfs/xfs_log_recover.c | 1 fs/xfs/xfs_mount.c | 2 fs/xfs/xfs_quota.h | 8 fs/xfs/xfs_rename.c | 1 fs/xfs/xfs_rtalloc.c | 1 fs/xfs/xfs_rw.c | 3 fs/xfs/xfs_trans.h | 47 + fs/xfs/xfs_trans_buf.c | 62 - fs/xfs/xfs_vnodeops.c | 8 70 files changed, 2151 insertions(+), 2592 deletions(-) Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Alex Elder <aelder@sgi.com>
2009-12-15 07:14:59 +08:00
{ XBF_ASYNC, "ASYNC" }, \
{ XBF_DONE, "DONE" }, \
{ XBF_STALE, "STALE" }, \
xfs: abort metadata writeback on permanent errors If we are doing aysnc writeback of metadata, we can get write errors but have nobody to report them to. At the moment, we simply attempt to reissue the write from io completion in the hope that it's a transient error. When it's not a transient error, the buffer is stuck forever in this loop, and we cannot break out of it. Eventually, unmount will hang because the AIL cannot be emptied and everything goes downhill from them. To solve this problem, only retry the write IO once before aborting it. We don't throw the buffer away because some transient errors can last minutes (e.g. FC path failover) or even hours (thin provisioned devices that have run out of backing space) before they go away. Hence we really want to keep trying until we can't try any more. Because the buffer was not cleaned, however, it does not get removed from the AIL and hence the next pass across the AIL will start IO on it again. As such, we still get the "retry forever" semantics that we currently have, but we allow other access to the buffer in the mean time. Meanwhile the filesystem can continue to modify the buffer and relog it, so the IO errors won't hang the log or the filesystem. Now when we are pushing the AIL, we can see all these "permanent IO error" buffers and we can issue a warning about failures before we retry the IO. We can also catch these buffers when unmounting an issue a corruption warning, too. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Ben Myers <bpm@sgi.com>
2013-12-12 13:34:38 +08:00
{ XBF_WRITE_FAIL, "WRITE_FAIL" }, \
{ XBF_SYNCIO, "SYNCIO" }, \
{ XBF_FUA, "FUA" }, \
{ XBF_FLUSH, "FLUSH" }, \
xfs: fix race while discarding buffers [V4] While xfs_buftarg_shrink() is freeing buffers from the dispose list (filled with buffers from lru list), there is a possibility to have xfs_buf_stale() racing with it, and removing buffers from dispose list before xfs_buftarg_shrink() does it. This happens because xfs_buftarg_shrink() handle the dispose list without locking and the test condition in xfs_buf_stale() checks for the buffer being in *any* list: if (!list_empty(&bp->b_lru)) If the buffer happens to be on dispose list, this causes the buffer counter of lru list (btp->bt_lru_nr) to be decremented twice (once in xfs_buftarg_shrink() and another in xfs_buf_stale()) causing a wrong account usage of the lru list. This may cause xfs_buftarg_shrink() to return a wrong value to the memory shrinker shrink_slab(), and such account error may also cause an underflowed value to be returned; since the counter is lower than the current number of items in the lru list, a decrement may happen when the counter is 0, causing an underflow on the counter. The fix uses a new flag field (and a new buffer flag) to serialize buffer handling during the shrink process. The new flag field has been designed to use btp->bt_lru_lock/unlock instead of xfs_buf_lock/unlock mechanism. dchinner, sandeen, aquini and aris also deserve credits for this. Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com> Reviewed-by: Ben Myers <bpm@sgi.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2012-08-11 02:01:51 +08:00
{ XBF_TRYLOCK, "TRYLOCK" }, /* should never be set */\
{ XBF_UNMAPPED, "UNMAPPED" }, /* ditto */\
xfs: event tracing support Convert the old xfs tracing support that could only be used with the out of tree kdb and xfsidbg patches to use the generic event tracer. To use it make sure CONFIG_EVENT_TRACING is enabled and then enable all xfs trace channels by: echo 1 > /sys/kernel/debug/tracing/events/xfs/enable or alternatively enable single events by just doing the same in one event subdirectory, e.g. echo 1 > /sys/kernel/debug/tracing/events/xfs/xfs_ihold/enable or set more complex filters, etc. In Documentation/trace/events.txt all this is desctribed in more detail. To reads the events do a cat /sys/kernel/debug/tracing/trace Compared to the last posting this patch converts the tracing mostly to the one tracepoint per callsite model that other users of the new tracing facility also employ. This allows a very fine-grained control of the tracing, a cleaner output of the traces and also enables the perf tool to use each tracepoint as a virtual performance counter, allowing us to e.g. count how often certain workloads git various spots in XFS. Take a look at http://lwn.net/Articles/346470/ for some examples. Also the btree tracing isn't included at all yet, as it will require additional core tracing features not in mainline yet, I plan to deliver it later. And the really nice thing about this patch is that it actually removes many lines of code while adding this nice functionality: fs/xfs/Makefile | 8 fs/xfs/linux-2.6/xfs_acl.c | 1 fs/xfs/linux-2.6/xfs_aops.c | 52 - fs/xfs/linux-2.6/xfs_aops.h | 2 fs/xfs/linux-2.6/xfs_buf.c | 117 +-- fs/xfs/linux-2.6/xfs_buf.h | 33 fs/xfs/linux-2.6/xfs_fs_subr.c | 3 fs/xfs/linux-2.6/xfs_ioctl.c | 1 fs/xfs/linux-2.6/xfs_ioctl32.c | 1 fs/xfs/linux-2.6/xfs_iops.c | 1 fs/xfs/linux-2.6/xfs_linux.h | 1 fs/xfs/linux-2.6/xfs_lrw.c | 87 -- fs/xfs/linux-2.6/xfs_lrw.h | 45 - fs/xfs/linux-2.6/xfs_super.c | 104 --- fs/xfs/linux-2.6/xfs_super.h | 7 fs/xfs/linux-2.6/xfs_sync.c | 1 fs/xfs/linux-2.6/xfs_trace.c | 75 ++ fs/xfs/linux-2.6/xfs_trace.h | 1369 +++++++++++++++++++++++++++++++++++++++++ fs/xfs/linux-2.6/xfs_vnode.h | 4 fs/xfs/quota/xfs_dquot.c | 110 --- fs/xfs/quota/xfs_dquot.h | 21 fs/xfs/quota/xfs_qm.c | 40 - fs/xfs/quota/xfs_qm_syscalls.c | 4 fs/xfs/support/ktrace.c | 323 --------- fs/xfs/support/ktrace.h | 85 -- fs/xfs/xfs.h | 16 fs/xfs/xfs_ag.h | 14 fs/xfs/xfs_alloc.c | 230 +----- fs/xfs/xfs_alloc.h | 27 fs/xfs/xfs_alloc_btree.c | 1 fs/xfs/xfs_attr.c | 107 --- fs/xfs/xfs_attr.h | 10 fs/xfs/xfs_attr_leaf.c | 14 fs/xfs/xfs_attr_sf.h | 40 - fs/xfs/xfs_bmap.c | 507 +++------------ fs/xfs/xfs_bmap.h | 49 - fs/xfs/xfs_bmap_btree.c | 6 fs/xfs/xfs_btree.c | 5 fs/xfs/xfs_btree_trace.h | 17 fs/xfs/xfs_buf_item.c | 87 -- fs/xfs/xfs_buf_item.h | 20 fs/xfs/xfs_da_btree.c | 3 fs/xfs/xfs_da_btree.h | 7 fs/xfs/xfs_dfrag.c | 2 fs/xfs/xfs_dir2.c | 8 fs/xfs/xfs_dir2_block.c | 20 fs/xfs/xfs_dir2_leaf.c | 21 fs/xfs/xfs_dir2_node.c | 27 fs/xfs/xfs_dir2_sf.c | 26 fs/xfs/xfs_dir2_trace.c | 216 ------ fs/xfs/xfs_dir2_trace.h | 72 -- fs/xfs/xfs_filestream.c | 8 fs/xfs/xfs_fsops.c | 2 fs/xfs/xfs_iget.c | 111 --- fs/xfs/xfs_inode.c | 67 -- fs/xfs/xfs_inode.h | 76 -- fs/xfs/xfs_inode_item.c | 5 fs/xfs/xfs_iomap.c | 85 -- fs/xfs/xfs_iomap.h | 8 fs/xfs/xfs_log.c | 181 +---- fs/xfs/xfs_log_priv.h | 20 fs/xfs/xfs_log_recover.c | 1 fs/xfs/xfs_mount.c | 2 fs/xfs/xfs_quota.h | 8 fs/xfs/xfs_rename.c | 1 fs/xfs/xfs_rtalloc.c | 1 fs/xfs/xfs_rw.c | 3 fs/xfs/xfs_trans.h | 47 + fs/xfs/xfs_trans_buf.c | 62 - fs/xfs/xfs_vnodeops.c | 8 70 files changed, 2151 insertions(+), 2592 deletions(-) Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Alex Elder <aelder@sgi.com>
2009-12-15 07:14:59 +08:00
{ _XBF_PAGES, "PAGES" }, \
2011-03-26 06:16:45 +08:00
{ _XBF_KMEM, "KMEM" }, \
{ _XBF_DELWRI_Q, "DELWRI_Q" }, \
xfs: use ->b_state to fix buffer I/O accounting release race We've had user reports of unmount hangs in xfs_wait_buftarg() that analysis shows is due to btp->bt_io_count == -1. bt_io_count represents the count of in-flight asynchronous buffers and thus should always be >= 0. xfs_wait_buftarg() waits for this value to stabilize to zero in order to ensure that all untracked (with respect to the lru) buffers have completed I/O processing before unmount proceeds to tear down in-core data structures. The value of -1 implies an I/O accounting decrement race. Indeed, the fact that xfs_buf_ioacct_dec() is called from xfs_buf_rele() (where the buffer lock is no longer held) means that bp->b_flags can be updated from an unsafe context. While a user-level reproducer is currently not available, some intrusive hacks to run racing buffer lookups/ioacct/releases from multiple threads was used to successfully manufacture this problem. Existing callers do not expect to acquire the buffer lock from xfs_buf_rele(). Therefore, we can not safely update ->b_flags from this context. It turns out that we already have separate buffer state bits and associated serialization for dealing with buffer LRU state in the form of ->b_state and ->b_lock. Therefore, replace the _XBF_IN_FLIGHT flag with a ->b_state variant, update the I/O accounting wrappers appropriately and make sure they are used with the correct locking. This ensures that buffer in-flight state can be modified at buffer release time without racing with modifications from a buffer lock holder. Fixes: 9c7504aa72b6 ("xfs: track and serialize in-flight async buffers against unmount") Cc: <stable@vger.kernel.org> # v4.8+ Signed-off-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Nikolay Borisov <nborisov@suse.com> Tested-by: Libor Pechacek <lpechacek@suse.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2017-05-31 23:22:52 +08:00
{ _XBF_COMPOUND, "COMPOUND" }
xfs: rework buffer dispose list tracking In converting the buffer lru lists to use the generic code, the locking for marking the buffers as on the dispose list was lost. This results in confusion in LRU buffer tracking and acocunting, resulting in reference counts being mucked up and filesystem beig unmountable. To fix this, introduce an internal buffer spinlock to protect the state field that holds the dispose list information. Because there is now locking needed around xfs_buf_lru_add/del, and they are used in exactly one place each two lines apart, get rid of the wrappers and code the logic directly in place. Further, the LRU emptying code used on unmount is less than optimal. Convert it to use a dispose list as per a normal shrinker walk, and repeat the walk that fills the dispose list until the LRU is empty. Thi avoids needing to drop and regain the LRU lock for every item being freed, and allows the same logic as the shrinker isolate call to be used. Simpler, easier to understand. Signed-off-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Glauber Costa <glommer@openvz.org> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Artem Bityutskiy <artem.bityutskiy@linux.intel.com> Cc: Arve Hjønnevåg <arve@android.com> Cc: Carlos Maiolino <cmaiolino@redhat.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Chuck Lever <chuck.lever@oracle.com> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: David Rientjes <rientjes@google.com> Cc: Gleb Natapov <gleb@redhat.com> Cc: Greg Thelen <gthelen@google.com> Cc: J. Bruce Fields <bfields@redhat.com> Cc: Jan Kara <jack@suse.cz> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Stultz <john.stultz@linaro.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Kent Overstreet <koverstreet@google.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: Thomas Hellstrom <thellstrom@vmware.com> Cc: Trond Myklebust <Trond.Myklebust@netapp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2013-08-28 08:18:06 +08:00
xfs: abort metadata writeback on permanent errors If we are doing aysnc writeback of metadata, we can get write errors but have nobody to report them to. At the moment, we simply attempt to reissue the write from io completion in the hope that it's a transient error. When it's not a transient error, the buffer is stuck forever in this loop, and we cannot break out of it. Eventually, unmount will hang because the AIL cannot be emptied and everything goes downhill from them. To solve this problem, only retry the write IO once before aborting it. We don't throw the buffer away because some transient errors can last minutes (e.g. FC path failover) or even hours (thin provisioned devices that have run out of backing space) before they go away. Hence we really want to keep trying until we can't try any more. Because the buffer was not cleaned, however, it does not get removed from the AIL and hence the next pass across the AIL will start IO on it again. As such, we still get the "retry forever" semantics that we currently have, but we allow other access to the buffer in the mean time. Meanwhile the filesystem can continue to modify the buffer and relog it, so the IO errors won't hang the log or the filesystem. Now when we are pushing the AIL, we can see all these "permanent IO error" buffers and we can issue a warning about failures before we retry the IO. We can also catch these buffers when unmounting an issue a corruption warning, too. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Ben Myers <bpm@sgi.com>
2013-12-12 13:34:38 +08:00
xfs: rework buffer dispose list tracking In converting the buffer lru lists to use the generic code, the locking for marking the buffers as on the dispose list was lost. This results in confusion in LRU buffer tracking and acocunting, resulting in reference counts being mucked up and filesystem beig unmountable. To fix this, introduce an internal buffer spinlock to protect the state field that holds the dispose list information. Because there is now locking needed around xfs_buf_lru_add/del, and they are used in exactly one place each two lines apart, get rid of the wrappers and code the logic directly in place. Further, the LRU emptying code used on unmount is less than optimal. Convert it to use a dispose list as per a normal shrinker walk, and repeat the walk that fills the dispose list until the LRU is empty. Thi avoids needing to drop and regain the LRU lock for every item being freed, and allows the same logic as the shrinker isolate call to be used. Simpler, easier to understand. Signed-off-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Glauber Costa <glommer@openvz.org> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Artem Bityutskiy <artem.bityutskiy@linux.intel.com> Cc: Arve Hjønnevåg <arve@android.com> Cc: Carlos Maiolino <cmaiolino@redhat.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Chuck Lever <chuck.lever@oracle.com> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: David Rientjes <rientjes@google.com> Cc: Gleb Natapov <gleb@redhat.com> Cc: Greg Thelen <gthelen@google.com> Cc: J. Bruce Fields <bfields@redhat.com> Cc: Jan Kara <jack@suse.cz> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Stultz <john.stultz@linaro.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Kent Overstreet <koverstreet@google.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: Thomas Hellstrom <thellstrom@vmware.com> Cc: Trond Myklebust <Trond.Myklebust@netapp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2013-08-28 08:18:06 +08:00
/*
* Internal state flags.
*/
#define XFS_BSTATE_DISPOSE (1 << 0) /* buffer being discarded */
xfs: use ->b_state to fix buffer I/O accounting release race We've had user reports of unmount hangs in xfs_wait_buftarg() that analysis shows is due to btp->bt_io_count == -1. bt_io_count represents the count of in-flight asynchronous buffers and thus should always be >= 0. xfs_wait_buftarg() waits for this value to stabilize to zero in order to ensure that all untracked (with respect to the lru) buffers have completed I/O processing before unmount proceeds to tear down in-core data structures. The value of -1 implies an I/O accounting decrement race. Indeed, the fact that xfs_buf_ioacct_dec() is called from xfs_buf_rele() (where the buffer lock is no longer held) means that bp->b_flags can be updated from an unsafe context. While a user-level reproducer is currently not available, some intrusive hacks to run racing buffer lookups/ioacct/releases from multiple threads was used to successfully manufacture this problem. Existing callers do not expect to acquire the buffer lock from xfs_buf_rele(). Therefore, we can not safely update ->b_flags from this context. It turns out that we already have separate buffer state bits and associated serialization for dealing with buffer LRU state in the form of ->b_state and ->b_lock. Therefore, replace the _XBF_IN_FLIGHT flag with a ->b_state variant, update the I/O accounting wrappers appropriately and make sure they are used with the correct locking. This ensures that buffer in-flight state can be modified at buffer release time without racing with modifications from a buffer lock holder. Fixes: 9c7504aa72b6 ("xfs: track and serialize in-flight async buffers against unmount") Cc: <stable@vger.kernel.org> # v4.8+ Signed-off-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Nikolay Borisov <nborisov@suse.com> Tested-by: Libor Pechacek <lpechacek@suse.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2017-05-31 23:22:52 +08:00
#define XFS_BSTATE_IN_FLIGHT (1 << 1) /* I/O in flight */
xfs: event tracing support Convert the old xfs tracing support that could only be used with the out of tree kdb and xfsidbg patches to use the generic event tracer. To use it make sure CONFIG_EVENT_TRACING is enabled and then enable all xfs trace channels by: echo 1 > /sys/kernel/debug/tracing/events/xfs/enable or alternatively enable single events by just doing the same in one event subdirectory, e.g. echo 1 > /sys/kernel/debug/tracing/events/xfs/xfs_ihold/enable or set more complex filters, etc. In Documentation/trace/events.txt all this is desctribed in more detail. To reads the events do a cat /sys/kernel/debug/tracing/trace Compared to the last posting this patch converts the tracing mostly to the one tracepoint per callsite model that other users of the new tracing facility also employ. This allows a very fine-grained control of the tracing, a cleaner output of the traces and also enables the perf tool to use each tracepoint as a virtual performance counter, allowing us to e.g. count how often certain workloads git various spots in XFS. Take a look at http://lwn.net/Articles/346470/ for some examples. Also the btree tracing isn't included at all yet, as it will require additional core tracing features not in mainline yet, I plan to deliver it later. And the really nice thing about this patch is that it actually removes many lines of code while adding this nice functionality: fs/xfs/Makefile | 8 fs/xfs/linux-2.6/xfs_acl.c | 1 fs/xfs/linux-2.6/xfs_aops.c | 52 - fs/xfs/linux-2.6/xfs_aops.h | 2 fs/xfs/linux-2.6/xfs_buf.c | 117 +-- fs/xfs/linux-2.6/xfs_buf.h | 33 fs/xfs/linux-2.6/xfs_fs_subr.c | 3 fs/xfs/linux-2.6/xfs_ioctl.c | 1 fs/xfs/linux-2.6/xfs_ioctl32.c | 1 fs/xfs/linux-2.6/xfs_iops.c | 1 fs/xfs/linux-2.6/xfs_linux.h | 1 fs/xfs/linux-2.6/xfs_lrw.c | 87 -- fs/xfs/linux-2.6/xfs_lrw.h | 45 - fs/xfs/linux-2.6/xfs_super.c | 104 --- fs/xfs/linux-2.6/xfs_super.h | 7 fs/xfs/linux-2.6/xfs_sync.c | 1 fs/xfs/linux-2.6/xfs_trace.c | 75 ++ fs/xfs/linux-2.6/xfs_trace.h | 1369 +++++++++++++++++++++++++++++++++++++++++ fs/xfs/linux-2.6/xfs_vnode.h | 4 fs/xfs/quota/xfs_dquot.c | 110 --- fs/xfs/quota/xfs_dquot.h | 21 fs/xfs/quota/xfs_qm.c | 40 - fs/xfs/quota/xfs_qm_syscalls.c | 4 fs/xfs/support/ktrace.c | 323 --------- fs/xfs/support/ktrace.h | 85 -- fs/xfs/xfs.h | 16 fs/xfs/xfs_ag.h | 14 fs/xfs/xfs_alloc.c | 230 +----- fs/xfs/xfs_alloc.h | 27 fs/xfs/xfs_alloc_btree.c | 1 fs/xfs/xfs_attr.c | 107 --- fs/xfs/xfs_attr.h | 10 fs/xfs/xfs_attr_leaf.c | 14 fs/xfs/xfs_attr_sf.h | 40 - fs/xfs/xfs_bmap.c | 507 +++------------ fs/xfs/xfs_bmap.h | 49 - fs/xfs/xfs_bmap_btree.c | 6 fs/xfs/xfs_btree.c | 5 fs/xfs/xfs_btree_trace.h | 17 fs/xfs/xfs_buf_item.c | 87 -- fs/xfs/xfs_buf_item.h | 20 fs/xfs/xfs_da_btree.c | 3 fs/xfs/xfs_da_btree.h | 7 fs/xfs/xfs_dfrag.c | 2 fs/xfs/xfs_dir2.c | 8 fs/xfs/xfs_dir2_block.c | 20 fs/xfs/xfs_dir2_leaf.c | 21 fs/xfs/xfs_dir2_node.c | 27 fs/xfs/xfs_dir2_sf.c | 26 fs/xfs/xfs_dir2_trace.c | 216 ------ fs/xfs/xfs_dir2_trace.h | 72 -- fs/xfs/xfs_filestream.c | 8 fs/xfs/xfs_fsops.c | 2 fs/xfs/xfs_iget.c | 111 --- fs/xfs/xfs_inode.c | 67 -- fs/xfs/xfs_inode.h | 76 -- fs/xfs/xfs_inode_item.c | 5 fs/xfs/xfs_iomap.c | 85 -- fs/xfs/xfs_iomap.h | 8 fs/xfs/xfs_log.c | 181 +---- fs/xfs/xfs_log_priv.h | 20 fs/xfs/xfs_log_recover.c | 1 fs/xfs/xfs_mount.c | 2 fs/xfs/xfs_quota.h | 8 fs/xfs/xfs_rename.c | 1 fs/xfs/xfs_rtalloc.c | 1 fs/xfs/xfs_rw.c | 3 fs/xfs/xfs_trans.h | 47 + fs/xfs/xfs_trans_buf.c | 62 - fs/xfs/xfs_vnodeops.c | 8 70 files changed, 2151 insertions(+), 2592 deletions(-) Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Alex Elder <aelder@sgi.com>
2009-12-15 07:14:59 +08:00
xfs: allow logical-sector sized O_DIRECT Some time ago, mkfs.xfs started picking the storage physical sector size as the default filesystem "sector size" in order to avoid RMW costs incurred by doing IOs at logical sector size alignments. However, this means that for a filesystem made with i.e. a 4k sector size on an "advanced format" 4k/512 disk, 512-byte direct IOs are no longer allowed. This means that XFS has essentially turned this AF drive into a hard 4K device, from the filesystem on up. XFS's mkfs-specified "sector size" is really just controlling the minimum size & alignment of filesystem metadata. There is no real need to tightly couple XFS's minimal metadata size to the minimum allowed direct IO size; XFS can continue doing metadata in optimal sizes, but still allow smaller DIOs for apps which issue them, for whatever reason. This patch adds a new field to the xfs_buftarg, so that we now track 2 sizes: 1) The metadata sector size, which is the minimum unit and alignment of IO which will be performed by metadata operations. 2) The device logical sector size The first is used internally by the file system for metadata alignment and IOs. The second is used for the minimum allowed direct IO alignment. This has passed xfstests on filesystems made with 4k sectors, including when run under the patch I sent to ignore XFS_IOC_DIOINFO, and issue 512 DIOs anyway. I also directly tested end of block behavior on preallocated, sparse, and existing files when we do a 512 IO into a 4k file on a 4k-sector filesystem, to be sure there were no unexpected behaviors. Signed-off-by: Eric Sandeen <sandeen@redhat.com> Reviewed-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2014-01-22 06:46:23 +08:00
/*
* The xfs_buftarg contains 2 notions of "sector size" -
*
* 1) The metadata sector size, which is the minimum unit and
* alignment of IO which will be performed by metadata operations.
* 2) The device logical sector size
*
* The first is specified at mkfs time, and is stored on-disk in the
* superblock's sb_sectsize.
*
* The latter is derived from the underlying device, and controls direct IO
* alignment constraints.
*/
typedef struct xfs_buftarg {
dev_t bt_dev;
struct block_device *bt_bdev;
struct dax_device *bt_daxdev;
struct xfs_mount *bt_mount;
unsigned int bt_meta_sectorsize;
size_t bt_meta_sectormask;
xfs: allow logical-sector sized O_DIRECT Some time ago, mkfs.xfs started picking the storage physical sector size as the default filesystem "sector size" in order to avoid RMW costs incurred by doing IOs at logical sector size alignments. However, this means that for a filesystem made with i.e. a 4k sector size on an "advanced format" 4k/512 disk, 512-byte direct IOs are no longer allowed. This means that XFS has essentially turned this AF drive into a hard 4K device, from the filesystem on up. XFS's mkfs-specified "sector size" is really just controlling the minimum size & alignment of filesystem metadata. There is no real need to tightly couple XFS's minimal metadata size to the minimum allowed direct IO size; XFS can continue doing metadata in optimal sizes, but still allow smaller DIOs for apps which issue them, for whatever reason. This patch adds a new field to the xfs_buftarg, so that we now track 2 sizes: 1) The metadata sector size, which is the minimum unit and alignment of IO which will be performed by metadata operations. 2) The device logical sector size The first is used internally by the file system for metadata alignment and IOs. The second is used for the minimum allowed direct IO alignment. This has passed xfstests on filesystems made with 4k sectors, including when run under the patch I sent to ignore XFS_IOC_DIOINFO, and issue 512 DIOs anyway. I also directly tested end of block behavior on preallocated, sparse, and existing files when we do a 512 IO into a 4k file on a 4k-sector filesystem, to be sure there were no unexpected behaviors. Signed-off-by: Eric Sandeen <sandeen@redhat.com> Reviewed-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2014-01-22 06:46:23 +08:00
size_t bt_logical_sectorsize;
size_t bt_logical_sectormask;
/* LRU control structures */
struct shrinker bt_shrinker;
struct list_lru bt_lru;
xfs: track and serialize in-flight async buffers against unmount Newly allocated XFS metadata buffers are added to the LRU once the hold count is released, which typically occurs after I/O completion. There is no other mechanism at current that tracks the existence or I/O state of a new buffer. Further, readahead I/O tends to be submitted asynchronously by nature, which means the I/O can remain in flight and actually complete long after the calling context is gone. This means that file descriptors or any other holds on the filesystem can be released, allowing the filesystem to be unmounted while I/O is still in flight. When I/O completion occurs, core data structures may have been freed, causing completion to run into invalid memory accesses and likely to panic. This problem is reproduced on XFS via directory readahead. A filesystem is mounted, a directory is opened/closed and the filesystem immediately unmounted. The open/close cycle triggers a directory readahead that if delayed long enough, runs buffer I/O completion after the unmount has completed. To address this problem, add a mechanism to track all in-flight, asynchronous buffers using per-cpu counters in the buftarg. The buffer is accounted on the first I/O submission after the current reference is acquired and unaccounted once the buffer is returned to the LRU or freed. Update xfs_wait_buftarg() to wait on all in-flight I/O before walking the LRU list. Once in-flight I/O has completed and the workqueue has drained, all new buffers should have been released onto the LRU. Signed-off-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-07-20 09:15:28 +08:00
struct percpu_counter bt_io_count;
} xfs_buftarg_t;
struct xfs_buf;
typedef void (*xfs_buf_iodone_t)(struct xfs_buf *);
#define XB_PAGES 2
struct xfs_buf_map {
xfs_daddr_t bm_bn; /* block number for I/O */
int bm_len; /* size of I/O */
};
#define DEFINE_SINGLE_BUF_MAP(map, blkno, numblk) \
struct xfs_buf_map (map) = { .bm_bn = (blkno), .bm_len = (numblk) };
struct xfs_buf_ops {
char *name;
union {
__be32 magic[2]; /* v4 and v5 on disk magic values */
__be16 magic16[2]; /* v4 and v5 on disk magic values */
};
void (*verify_read)(struct xfs_buf *);
void (*verify_write)(struct xfs_buf *);
xfs_failaddr_t (*verify_struct)(struct xfs_buf *bp);
};
typedef struct xfs_buf {
/*
* first cacheline holds all the fields needed for an uncontended cache
* hit to be fully processed. The semaphore straddles the cacheline
* boundary, but the counter and lock sits on the first cacheline,
* which is the only bit that is touched if we hit the semaphore
* fast-path on locking.
*/
struct rhash_head b_rhash_head; /* pag buffer hash node */
xfs_daddr_t b_bn; /* block number of buffer */
int b_length; /* size of buffer in BBs */
atomic_t b_hold; /* reference count */
xfs: add a lru to the XFS buffer cache Introduce a per-buftarg LRU for memory reclaim to operate on. This is the last piece we need to put in place so that we can fully control the buffer lifecycle. This allows XFS to be responsibile for maintaining the working set of buffers under memory pressure instead of relying on the VM reclaim not to take pages we need out from underneath us. The implementation introduces a b_lru_ref counter into the buffer. This is currently set to 1 whenever the buffer is referenced and so is used to determine if the buffer should be added to the LRU or not when freed. Effectively it allows lazy LRU initialisation of the buffer so we do not need to touch the LRU list and locks in xfs_buf_find(). Instead, when the buffer is being released and we drop the last reference to it, we check the b_lru_ref count and if it is none zero we re-add the buffer reference and add the inode to the LRU. The b_lru_ref counter is decremented by the shrinker, and whenever the shrinker comes across a buffer with a zero b_lru_ref counter, if released the LRU reference on the buffer. In the absence of a lookup race, this will result in the buffer being freed. This counting mechanism is used instead of a reference flag so that it is simple to re-introduce buffer-type specific reclaim reference counts to prioritise reclaim more effectively. We still have all those hooks in the XFS code, so this will provide the infrastructure to re-implement that functionality. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
2010-12-02 13:30:55 +08:00
atomic_t b_lru_ref; /* lru reclaim ref count */
xfs_buf_flags_t b_flags; /* status flags */
struct semaphore b_sema; /* semaphore for lockables */
xfs: fix race while discarding buffers [V4] While xfs_buftarg_shrink() is freeing buffers from the dispose list (filled with buffers from lru list), there is a possibility to have xfs_buf_stale() racing with it, and removing buffers from dispose list before xfs_buftarg_shrink() does it. This happens because xfs_buftarg_shrink() handle the dispose list without locking and the test condition in xfs_buf_stale() checks for the buffer being in *any* list: if (!list_empty(&bp->b_lru)) If the buffer happens to be on dispose list, this causes the buffer counter of lru list (btp->bt_lru_nr) to be decremented twice (once in xfs_buftarg_shrink() and another in xfs_buf_stale()) causing a wrong account usage of the lru list. This may cause xfs_buftarg_shrink() to return a wrong value to the memory shrinker shrink_slab(), and such account error may also cause an underflowed value to be returned; since the counter is lower than the current number of items in the lru list, a decrement may happen when the counter is 0, causing an underflow on the counter. The fix uses a new flag field (and a new buffer flag) to serialize buffer handling during the shrink process. The new flag field has been designed to use btp->bt_lru_lock/unlock instead of xfs_buf_lock/unlock mechanism. dchinner, sandeen, aquini and aris also deserve credits for this. Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com> Reviewed-by: Ben Myers <bpm@sgi.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2012-08-11 02:01:51 +08:00
/*
* concurrent access to b_lru and b_lru_flags are protected by
* bt_lru_lock and not by b_sema
*/
xfs: add a lru to the XFS buffer cache Introduce a per-buftarg LRU for memory reclaim to operate on. This is the last piece we need to put in place so that we can fully control the buffer lifecycle. This allows XFS to be responsibile for maintaining the working set of buffers under memory pressure instead of relying on the VM reclaim not to take pages we need out from underneath us. The implementation introduces a b_lru_ref counter into the buffer. This is currently set to 1 whenever the buffer is referenced and so is used to determine if the buffer should be added to the LRU or not when freed. Effectively it allows lazy LRU initialisation of the buffer so we do not need to touch the LRU list and locks in xfs_buf_find(). Instead, when the buffer is being released and we drop the last reference to it, we check the b_lru_ref count and if it is none zero we re-add the buffer reference and add the inode to the LRU. The b_lru_ref counter is decremented by the shrinker, and whenever the shrinker comes across a buffer with a zero b_lru_ref counter, if released the LRU reference on the buffer. In the absence of a lookup race, this will result in the buffer being freed. This counting mechanism is used instead of a reference flag so that it is simple to re-introduce buffer-type specific reclaim reference counts to prioritise reclaim more effectively. We still have all those hooks in the XFS code, so this will provide the infrastructure to re-implement that functionality. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
2010-12-02 13:30:55 +08:00
struct list_head b_lru; /* lru list */
xfs: rework buffer dispose list tracking In converting the buffer lru lists to use the generic code, the locking for marking the buffers as on the dispose list was lost. This results in confusion in LRU buffer tracking and acocunting, resulting in reference counts being mucked up and filesystem beig unmountable. To fix this, introduce an internal buffer spinlock to protect the state field that holds the dispose list information. Because there is now locking needed around xfs_buf_lru_add/del, and they are used in exactly one place each two lines apart, get rid of the wrappers and code the logic directly in place. Further, the LRU emptying code used on unmount is less than optimal. Convert it to use a dispose list as per a normal shrinker walk, and repeat the walk that fills the dispose list until the LRU is empty. Thi avoids needing to drop and regain the LRU lock for every item being freed, and allows the same logic as the shrinker isolate call to be used. Simpler, easier to understand. Signed-off-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Glauber Costa <glommer@openvz.org> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Artem Bityutskiy <artem.bityutskiy@linux.intel.com> Cc: Arve Hjønnevåg <arve@android.com> Cc: Carlos Maiolino <cmaiolino@redhat.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Chuck Lever <chuck.lever@oracle.com> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: David Rientjes <rientjes@google.com> Cc: Gleb Natapov <gleb@redhat.com> Cc: Greg Thelen <gthelen@google.com> Cc: J. Bruce Fields <bfields@redhat.com> Cc: Jan Kara <jack@suse.cz> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Stultz <john.stultz@linaro.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Kent Overstreet <koverstreet@google.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: Thomas Hellstrom <thellstrom@vmware.com> Cc: Trond Myklebust <Trond.Myklebust@netapp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2013-08-28 08:18:06 +08:00
spinlock_t b_lock; /* internal state lock */
unsigned int b_state; /* internal state flags */
int b_io_error; /* internal IO error state */
wait_queue_head_t b_waiters; /* unpin waiters */
struct list_head b_list;
struct xfs_perag *b_pag; /* contains rbtree root */
xfs_buftarg_t *b_target; /* buffer target (device) */
void *b_addr; /* virtual address of buffer */
struct work_struct b_ioend_work;
struct workqueue_struct *b_ioend_wq; /* I/O completion wq */
xfs_buf_iodone_t b_iodone; /* I/O completion function */
struct completion b_iowait; /* queue for I/O waiters */
void *b_log_item;
struct list_head b_li_list; /* Log items list head */
struct xfs_trans *b_transp;
struct page **b_pages; /* array of page pointers */
struct page *b_page_array[XB_PAGES]; /* inline pages */
struct xfs_buf_map *b_maps; /* compound buffer map */
struct xfs_buf_map __b_map; /* inline compound buffer map */
int b_map_count;
int b_io_length; /* IO size in BBs */
atomic_t b_pin_count; /* pin count */
atomic_t b_io_remaining; /* #outstanding I/O requests */
unsigned int b_page_count; /* size of page array */
unsigned int b_offset; /* page offset in first page */
int b_error; /* error code on I/O */
/*
* async write failure retry count. Initialised to zero on the first
* failure, then when it exceeds the maximum configured without a
* success the write is considered to be failed permanently and the
* iodone handler will take appropriate action.
*
* For retry timeouts, we record the jiffie of the first failure. This
* means that we can change the retry timeout for buffers already under
* I/O and thus avoid getting stuck in a retry loop with a long timeout.
*
* last_error is used to ensure that we are getting repeated errors, not
* different errors. e.g. a block device might change ENOSPC to EIO when
* a failure timeout occurs, so we want to re-initialise the error
* retry behaviour appropriately when that happens.
*/
int b_retries;
unsigned long b_first_retry_time; /* in jiffies */
int b_last_error;
const struct xfs_buf_ops *b_ops;
} xfs_buf_t;
/* Finding and Reading Buffers */
struct xfs_buf *xfs_buf_incore(struct xfs_buftarg *target,
xfs_daddr_t blkno, size_t numblks,
xfs_buf_flags_t flags);
struct xfs_buf *_xfs_buf_alloc(struct xfs_buftarg *target,
struct xfs_buf_map *map, int nmaps,
xfs_buf_flags_t flags);
static inline struct xfs_buf *
xfs_buf_alloc(
struct xfs_buftarg *target,
xfs_daddr_t blkno,
size_t numblks,
xfs_buf_flags_t flags)
{
DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
return _xfs_buf_alloc(target, &map, 1, flags);
}
struct xfs_buf *xfs_buf_get_map(struct xfs_buftarg *target,
struct xfs_buf_map *map, int nmaps,
xfs_buf_flags_t flags);
struct xfs_buf *xfs_buf_read_map(struct xfs_buftarg *target,
struct xfs_buf_map *map, int nmaps,
xfs_buf_flags_t flags,
const struct xfs_buf_ops *ops);
void xfs_buf_readahead_map(struct xfs_buftarg *target,
struct xfs_buf_map *map, int nmaps,
const struct xfs_buf_ops *ops);
static inline struct xfs_buf *
xfs_buf_get(
struct xfs_buftarg *target,
xfs_daddr_t blkno,
size_t numblks,
xfs_buf_flags_t flags)
{
DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
return xfs_buf_get_map(target, &map, 1, flags);
}
static inline struct xfs_buf *
xfs_buf_read(
struct xfs_buftarg *target,
xfs_daddr_t blkno,
size_t numblks,
xfs_buf_flags_t flags,
const struct xfs_buf_ops *ops)
{
DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
return xfs_buf_read_map(target, &map, 1, flags, ops);
}
static inline void
xfs_buf_readahead(
struct xfs_buftarg *target,
xfs_daddr_t blkno,
size_t numblks,
const struct xfs_buf_ops *ops)
{
DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
return xfs_buf_readahead_map(target, &map, 1, ops);
}
void xfs_buf_set_empty(struct xfs_buf *bp, size_t numblks);
int xfs_buf_associate_memory(struct xfs_buf *bp, void *mem, size_t length);
struct xfs_buf *xfs_buf_get_uncached(struct xfs_buftarg *target, size_t numblks,
int flags);
int xfs_buf_read_uncached(struct xfs_buftarg *target, xfs_daddr_t daddr,
size_t numblks, int flags, struct xfs_buf **bpp,
const struct xfs_buf_ops *ops);
void xfs_buf_hold(struct xfs_buf *bp);
/* Releasing Buffers */
extern void xfs_buf_free(xfs_buf_t *);
extern void xfs_buf_rele(xfs_buf_t *);
/* Locking and Unlocking Buffers */
extern int xfs_buf_trylock(xfs_buf_t *);
extern void xfs_buf_lock(xfs_buf_t *);
extern void xfs_buf_unlock(xfs_buf_t *);
#define xfs_buf_islocked(bp) \
((bp)->b_sema.count <= 0)
/* Buffer Read and Write Routines */
extern int xfs_bwrite(struct xfs_buf *bp);
extern void xfs_buf_ioend(struct xfs_buf *bp);
extern void __xfs_buf_ioerror(struct xfs_buf *bp, int error,
xfs_failaddr_t failaddr);
#define xfs_buf_ioerror(bp, err) __xfs_buf_ioerror((bp), (err), __this_address)
extern void xfs_buf_ioerror_alert(struct xfs_buf *, const char *func);
extern int __xfs_buf_submit(struct xfs_buf *bp, bool);
static inline int xfs_buf_submit(struct xfs_buf *bp)
{
bool wait = bp->b_flags & XBF_ASYNC ? false : true;
return __xfs_buf_submit(bp, wait);
}
extern void xfs_buf_iomove(xfs_buf_t *, size_t, size_t, void *,
xfs_buf_rw_t);
#define xfs_buf_zero(bp, off, len) \
xfs_buf_iomove((bp), (off), (len), NULL, XBRW_ZERO)
/* Buffer Utility Routines */
extern void *xfs_buf_offset(struct xfs_buf *, size_t);
extern void xfs_buf_stale(struct xfs_buf *bp);
/* Delayed Write Buffer Routines */
extern void xfs_buf_delwri_cancel(struct list_head *);
xfs: on-stack delayed write buffer lists Queue delwri buffers on a local on-stack list instead of a per-buftarg one, and write back the buffers per-process instead of by waking up xfsbufd. This is now easily doable given that we have very few places left that write delwri buffers: - log recovery: Only done at mount time, and already forcing out the buffers synchronously using xfs_flush_buftarg - quotacheck: Same story. - dquot reclaim: Writes out dirty dquots on the LRU under memory pressure. We might want to look into doing more of this via xfsaild, but it's already more optimal than the synchronous inode reclaim that writes each buffer synchronously. - xfsaild: This is the main beneficiary of the change. By keeping a local list of buffers to write we reduce latency of writing out buffers, and more importably we can remove all the delwri list promotions which were hitting the buffer cache hard under sustained metadata loads. The implementation is very straight forward - xfs_buf_delwri_queue now gets a new list_head pointer that it adds the delwri buffers to, and all callers need to eventually submit the list using xfs_buf_delwi_submit or xfs_buf_delwi_submit_nowait. Buffers that already are on a delwri list are skipped in xfs_buf_delwri_queue, assuming they already are on another delwri list. The biggest change to pass down the buffer list was done to the AIL pushing. Now that we operate on buffers the trylock, push and pushbuf log item methods are merged into a single push routine, which tries to lock the item, and if possible add the buffer that needs writeback to the buffer list. This leads to much simpler code than the previous split but requires the individual IOP_PUSH instances to unlock and reacquire the AIL around calls to blocking routines. Given that xfsailds now also handle writing out buffers, the conditions for log forcing and the sleep times needed some small changes. The most important one is that we consider an AIL busy as long we still have buffers to push, and the other one is that we do increment the pushed LSN for buffers that are under flushing at this moment, but still count them towards the stuck items for restart purposes. Without this we could hammer on stuck items without ever forcing the log and not make progress under heavy random delete workloads on fast flash storage devices. [ Dave Chinner: - rebase on previous patches. - improved comments for XBF_DELWRI_Q handling - fix XBF_ASYNC handling in queue submission (test 106 failure) - rename delwri submit function buffer list parameters for clarity - xfs_efd_item_push() should return XFS_ITEM_PINNED ] Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Mark Tinguely <tinguely@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2012-04-23 13:58:39 +08:00
extern bool xfs_buf_delwri_queue(struct xfs_buf *, struct list_head *);
extern int xfs_buf_delwri_submit(struct list_head *);
extern int xfs_buf_delwri_submit_nowait(struct list_head *);
xfs: push buffer of flush locked dquot to avoid quotacheck deadlock Reclaim during quotacheck can lead to deadlocks on the dquot flush lock: - Quotacheck populates a local delwri queue with the physical dquot buffers. - Quotacheck performs the xfs_qm_dqusage_adjust() bulkstat and dirties all of the dquots. - Reclaim kicks in and attempts to flush a dquot whose buffer is already queud on the quotacheck queue. The flush succeeds but queueing to the reclaim delwri queue fails as the backing buffer is already queued. The flush unlock is now deferred to I/O completion of the buffer from the quotacheck queue. - The dqadjust bulkstat continues and dirties the recently flushed dquot once again. - Quotacheck proceeds to the xfs_qm_flush_one() walk which requires the flush lock to update the backing buffers with the in-core recalculated values. It deadlocks on the redirtied dquot as the flush lock was already acquired by reclaim, but the buffer resides on the local delwri queue which isn't submitted until the end of quotacheck. This is reproduced by running quotacheck on a filesystem with a couple million inodes in low memory (512MB-1GB) situations. This is a regression as of commit 43ff2122e6 ("xfs: on-stack delayed write buffer lists"), which removed a trylock and buffer I/O submission from the quotacheck dquot flush sequence. Quotacheck first resets and collects the physical dquot buffers in a delwri queue. Then, it traverses the filesystem inodes via bulkstat, updates the in-core dquots, flushes the corrected dquots to the backing buffers and finally submits the delwri queue for I/O. Since the backing buffers are queued across the entire quotacheck operation, dquot reclaim cannot possibly complete a dquot flush before quotacheck completes. Therefore, quotacheck must submit the buffer for I/O in order to cycle the flush lock and flush the dirty in-core dquot to the buffer. Add a delwri queue buffer push mechanism to submit an individual buffer for I/O without losing the delwri queue status and use it from quotacheck to avoid the deadlock. This restores quotacheck behavior to as before the regression was introduced. Reported-by: Martin Svec <martin.svec@zoner.cz> Signed-off-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2017-06-15 12:21:45 +08:00
extern int xfs_buf_delwri_pushbuf(struct xfs_buf *, struct list_head *);
/* Buffer Daemon Setup Routines */
extern int xfs_buf_init(void);
extern void xfs_buf_terminate(void);
/*
* These macros use the IO block map rather than b_bn. b_bn is now really
* just for the buffer cache index for cached buffers. As IO does not use b_bn
* anymore, uncached buffers do not use b_bn at all and hence must modify the IO
* map directly. Uncached buffers are not allowed to be discontiguous, so this
* is safe to do.
*
* In future, uncached buffers will pass the block number directly to the io
* request function and hence these macros will go away at that point.
*/
#define XFS_BUF_ADDR(bp) ((bp)->b_maps[0].bm_bn)
#define XFS_BUF_SET_ADDR(bp, bno) ((bp)->b_maps[0].bm_bn = (xfs_daddr_t)(bno))
void xfs_buf_set_ref(struct xfs_buf *bp, int lru_ref);
/*
* If the buffer is already on the LRU, do nothing. Otherwise set the buffer
* up with a reference count of 0 so it will be tossed from the cache when
* released.
*/
static inline void xfs_buf_oneshot(struct xfs_buf *bp)
{
if (!list_empty(&bp->b_lru) || atomic_read(&bp->b_lru_ref) > 1)
return;
atomic_set(&bp->b_lru_ref, 0);
}
static inline int xfs_buf_ispinned(struct xfs_buf *bp)
{
return atomic_read(&bp->b_pin_count);
}
static inline void xfs_buf_relse(xfs_buf_t *bp)
{
xfs: fix error handling for synchronous writes If we get an IO error on a synchronous superblock write, we attach an error release function to it so that when the last reference goes away the release function is called and the buffer is invalidated and unlocked. The buffer is left locked until the release function is called so that other concurrent users of the buffer will be locked out until the buffer error is fully processed. Unfortunately, for the superblock buffer the filesyetm itself holds a reference to the buffer which prevents the reference count from dropping to zero and the release function being called. As a result, once an IO error occurs on a sync write, the buffer will never be unlocked and all future attempts to lock the buffer will hang. To make matters worse, this problems is not unique to such buffers; if there is a concurrent _xfs_buf_find() running, the lookup will grab a reference to the buffer and then wait on the buffer lock, preventing the reference count from ever falling to zero and hence unlocking the buffer. As such, the whole b_relse function implementation is broken because it cannot rely on the buffer reference count falling to zero to unlock the errored buffer. The synchronous write error path is the only path that uses this callback - it is used to ensure that the synchronous waiter gets the buffer error before the error state is cleared from the buffer by the release function. Given that the only sychronous buffer writes now go through xfs_bwrite and the error path in question can only occur for a write of a dirty, logged buffer, we can move most of the b_relse processing to happen inline in xfs_buf_iodone_callbacks, just like a normal I/O completion. In addition to that we make sure the error is not cleared in xfs_buf_iodone_callbacks, so that xfs_bwrite can reliably check it. Given that xfs_bwrite keeps the buffer locked until it has waited for it and checked the error this allows to reliably propagate the error to the caller, and make sure that the buffer is reliably unlocked. Given that xfs_buf_iodone_callbacks was the only instance of the b_relse callback we can remove it entirely. Based on earlier patches by Dave Chinner and Ajeet Yadav. Signed-off-by: Christoph Hellwig <hch@lst.de> Reported-by: Ajeet Yadav <ajeet.yadav.77@gmail.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Alex Elder <aelder@sgi.com>
2011-01-07 21:02:23 +08:00
xfs_buf_unlock(bp);
xfs_buf_rele(bp);
}
static inline int
xfs_buf_verify_cksum(struct xfs_buf *bp, unsigned long cksum_offset)
{
return xfs_verify_cksum(bp->b_addr, BBTOB(bp->b_length),
cksum_offset);
}
static inline void
xfs_buf_update_cksum(struct xfs_buf *bp, unsigned long cksum_offset)
{
xfs_update_cksum(bp->b_addr, BBTOB(bp->b_length),
cksum_offset);
}
/*
* Handling of buftargs.
*/
extern xfs_buftarg_t *xfs_alloc_buftarg(struct xfs_mount *,
struct block_device *, struct dax_device *);
extern void xfs_free_buftarg(struct xfs_buftarg *);
extern void xfs_wait_buftarg(xfs_buftarg_t *);
extern int xfs_setsize_buftarg(xfs_buftarg_t *, unsigned int);
#define xfs_getsize_buftarg(buftarg) block_size((buftarg)->bt_bdev)
#define xfs_readonly_buftarg(buftarg) bdev_read_only((buftarg)->bt_bdev)
int xfs_buf_reverify(struct xfs_buf *bp, const struct xfs_buf_ops *ops);
bool xfs_verify_magic(struct xfs_buf *bp, __be32 dmagic);
bool xfs_verify_magic16(struct xfs_buf *bp, __be16 dmagic);
#endif /* __XFS_BUF_H__ */