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authorDave Chinner <dchinner@redhat.com>2015-02-23 22:37:08 +1100
committerSasha Levin <sasha.levin@oracle.com>2015-04-24 17:14:13 -0400
commit48ca7d78ff4efccbf3d670774d29dd52b7af912d (patch)
treea4c5b8d74dc27af5f715d6f181e4e3be88c14800
parenta69957362258b8932fe4df1433b1fdea8072ba04 (diff)
downloadlinux-linaro-stable-48ca7d78ff4efccbf3d670774d29dd52b7af912d.tar.gz
xfs: ensure truncate forces zeroed blocks to disk
[ Upstream commit 5885ebda878b47c4b4602d4b0410cb4b282af024 ] A new fsync vs power fail test in xfstests indicated that XFS can have unreliable data consistency when doing extending truncates that require block zeroing. The blocks beyond EOF get zeroed in memory, but we never force those changes to disk before we run the transaction that extends the file size and exposes those blocks to userspace. This can result in the blocks not being correctly zeroed after a crash. Because in-memory behaviour is correct, tools like fsx don't pick up any coherency problems - it's not until the filesystem is shutdown or the system crashes after writing the truncate transaction to the journal but before the zeroed data in the page cache is flushed that the issue is exposed. Fix this by also flushing the dirty data in memory region between the old size and new size when we've found blocks that need zeroing in the truncate process. Reported-by: Liu Bo <bo.li.liu@oracle.com> cc: <stable@vger.kernel.org> Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Brian Foster <bfoster@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
-rw-r--r--fs/xfs/xfs_file.c14
-rw-r--r--fs/xfs/xfs_inode.h5
-rw-r--r--fs/xfs/xfs_iops.c36
3 files changed, 27 insertions, 28 deletions
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index eb596b419942..b28f0d680cb5 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -363,7 +363,8 @@ STATIC int /* error (positive) */
xfs_zero_last_block(
struct xfs_inode *ip,
xfs_fsize_t offset,
- xfs_fsize_t isize)
+ xfs_fsize_t isize,
+ bool *did_zeroing)
{
struct xfs_mount *mp = ip->i_mount;
xfs_fileoff_t last_fsb = XFS_B_TO_FSBT(mp, isize);
@@ -391,6 +392,7 @@ xfs_zero_last_block(
zero_len = mp->m_sb.sb_blocksize - zero_offset;
if (isize + zero_len > offset)
zero_len = offset - isize;
+ *did_zeroing = true;
return xfs_iozero(ip, isize, zero_len);
}
@@ -409,7 +411,8 @@ int /* error (positive) */
xfs_zero_eof(
struct xfs_inode *ip,
xfs_off_t offset, /* starting I/O offset */
- xfs_fsize_t isize) /* current inode size */
+ xfs_fsize_t isize, /* current inode size */
+ bool *did_zeroing)
{
struct xfs_mount *mp = ip->i_mount;
xfs_fileoff_t start_zero_fsb;
@@ -431,7 +434,7 @@ xfs_zero_eof(
* We only zero a part of that block so it is handled specially.
*/
if (XFS_B_FSB_OFFSET(mp, isize) != 0) {
- error = xfs_zero_last_block(ip, offset, isize);
+ error = xfs_zero_last_block(ip, offset, isize, did_zeroing);
if (error)
return error;
}
@@ -491,6 +494,7 @@ xfs_zero_eof(
if (error)
return error;
+ *did_zeroing = true;
start_zero_fsb = imap.br_startoff + imap.br_blockcount;
ASSERT(start_zero_fsb <= (end_zero_fsb + 1));
}
@@ -529,13 +533,15 @@ restart:
* having to redo all checks before.
*/
if (*pos > i_size_read(inode)) {
+ bool zero = false;
+
if (*iolock == XFS_IOLOCK_SHARED) {
xfs_rw_iunlock(ip, *iolock);
*iolock = XFS_IOLOCK_EXCL;
xfs_rw_ilock(ip, *iolock);
goto restart;
}
- error = xfs_zero_eof(ip, *pos, i_size_read(inode));
+ error = xfs_zero_eof(ip, *pos, i_size_read(inode), &zero);
if (error)
return error;
}
diff --git a/fs/xfs/xfs_inode.h b/fs/xfs/xfs_inode.h
index 9af2882e1f4c..cb6ab0ad91a4 100644
--- a/fs/xfs/xfs_inode.h
+++ b/fs/xfs/xfs_inode.h
@@ -379,8 +379,9 @@ int xfs_droplink(struct xfs_trans *, struct xfs_inode *);
int xfs_bumplink(struct xfs_trans *, struct xfs_inode *);
/* from xfs_file.c */
-int xfs_zero_eof(struct xfs_inode *, xfs_off_t, xfs_fsize_t);
-int xfs_iozero(struct xfs_inode *, loff_t, size_t);
+int xfs_zero_eof(struct xfs_inode *ip, xfs_off_t offset,
+ xfs_fsize_t isize, bool *did_zeroing);
+int xfs_iozero(struct xfs_inode *ip, loff_t pos, size_t count);
#define IHOLD(ip) \
diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
index ec6dcdc181ee..d2273d243990 100644
--- a/fs/xfs/xfs_iops.c
+++ b/fs/xfs/xfs_iops.c
@@ -744,6 +744,7 @@ xfs_setattr_size(
int error;
uint lock_flags = 0;
uint commit_flags = 0;
+ bool did_zeroing = false;
trace_xfs_setattr(ip);
@@ -787,20 +788,16 @@ xfs_setattr_size(
return error;
/*
- * Now we can make the changes. Before we join the inode to the
- * transaction, take care of the part of the truncation that must be
- * done without the inode lock. This needs to be done before joining
- * the inode to the transaction, because the inode cannot be unlocked
- * once it is a part of the transaction.
+ * File data changes must be complete before we start the transaction to
+ * modify the inode. This needs to be done before joining the inode to
+ * the transaction because the inode cannot be unlocked once it is a
+ * part of the transaction.
+ *
+ * Start with zeroing any data block beyond EOF that we may expose on
+ * file extension.
*/
if (newsize > oldsize) {
- /*
- * Do the first part of growing a file: zero any data in the
- * last block that is beyond the old EOF. We need to do this
- * before the inode is joined to the transaction to modify
- * i_size.
- */
- error = xfs_zero_eof(ip, newsize, oldsize);
+ error = xfs_zero_eof(ip, newsize, oldsize, &did_zeroing);
if (error)
return error;
}
@@ -810,23 +807,18 @@ xfs_setattr_size(
* any previous writes that are beyond the on disk EOF and the new
* EOF that have not been written out need to be written here. If we
* do not write the data out, we expose ourselves to the null files
- * problem.
- *
- * Only flush from the on disk size to the smaller of the in memory
- * file size or the new size as that's the range we really care about
- * here and prevents waiting for other data not within the range we
- * care about here.
+ * problem. Note that this includes any block zeroing we did above;
+ * otherwise those blocks may not be zeroed after a crash.
*/
- if (oldsize != ip->i_d.di_size && newsize > ip->i_d.di_size) {
+ if (newsize > ip->i_d.di_size &&
+ (oldsize != ip->i_d.di_size || did_zeroing)) {
error = filemap_write_and_wait_range(VFS_I(ip)->i_mapping,
ip->i_d.di_size, newsize);
if (error)
return error;
}
- /*
- * Wait for all direct I/O to complete.
- */
+ /* Now wait for all direct I/O to complete. */
inode_dio_wait(inode);
/*