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xfs: split xfs_itruncate_finish

Browse source 
Split the guts of xfs_itruncate_finish that loop over the existing extents
and calls xfs_bunmapi on them into a new helper, xfs_itruncate_externs.
Make xfs_attr_inactive call it directly instead of xfs_itruncate_finish,
which allows to simplify the latter a lot, by only letting it deal with
the data fork.  As a result xfs_itruncate_finish is renamed to
xfs_itruncate_data to make its use case more obvious.

Also remove the sync parameter from xfs_itruncate_data, which has been
unessecary since the introduction of the busy extent list in 2002, and
completely dead code since 2003 when the XFS_BMAPI_ASYNC parameter was
made a no-op.

I can't actually see why the xfs_attr_inactive needs to set the transaction
sync, but let's keep this patch simple and without changes in behaviour.

Also avoid passing a useless argument to xfs_isize_check, and make it
private to xfs_inode.c.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Alex Elder <aelder@sgi.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
This commit is contained in:
Christoph Hellwig 2011-07-08 14:34:34 +02:00
parent 857b9778d8
commit 8f04c47aa9
7 changed files with 155 additions and 277 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

10
fs/xfs/linux-2.6/xfs_iops.c
View file

@ -879,15 +879,7 @@ xfs_setattr_size(
ip->i_size = iattr->ia_size;
} else if (iattr->ia_size <= ip->i_size ||
(iattr->ia_size == 0 && ip->i_d.di_nextents)) {
/*
* Signal a sync transaction unless we are truncating an
* already unlinked file on a wsync filesystem.
*/
error = xfs_itruncate_finish(&tp, ip, iattr->ia_size,
XFS_DATA_FORK,
((ip->i_d.di_nlink != 0 ||
!(mp->m_flags & XFS_MOUNT_WSYNC))
? 1 : 0));
error = xfs_itruncate_data(&tp, ip, iattr->ia_size);
if (error)
goto out_trans_abort;

4
fs/xfs/linux-2.6/xfs_trace.h
View file

@ -1055,8 +1055,8 @@ DECLARE_EVENT_CLASS(xfs_itrunc_class,
DEFINE_EVENT(xfs_itrunc_class, name, \
TP_PROTO(struct xfs_inode *ip, xfs_fsize_t new_size), \
TP_ARGS(ip, new_size))
DEFINE_ITRUNC_EVENT(xfs_itruncate_finish_start);
DEFINE_ITRUNC_EVENT(xfs_itruncate_finish_end);
DEFINE_ITRUNC_EVENT(xfs_itruncate_data_start);
DEFINE_ITRUNC_EVENT(xfs_itruncate_data_end);
TRACE_EVENT(xfs_pagecache_inval,
TP_PROTO(struct xfs_inode *ip, xfs_off_t start, xfs_off_t finish),

2
fs/xfs/quota/xfs_qm_syscalls.c
View file

@ -263,7 +263,7 @@ xfs_qm_scall_trunc_qfile(
xfs_ilock(ip, XFS_ILOCK_EXCL);
xfs_trans_ijoin(tp, ip);
error = xfs_itruncate_finish(&tp, ip, 0, XFS_DATA_FORK, 1);
error = xfs_itruncate_data(&tp, ip, 0);
if (error) {
xfs_trans_cancel(tp, XFS_TRANS_RELEASE_LOG_RES |
XFS_TRANS_ABORT);

22
fs/xfs/xfs_attr.c
View file

@ -822,17 +822,21 @@ xfs_attr_inactive(xfs_inode_t *dp)
error = xfs_attr_root_inactive(&trans, dp);
if (error)
goto out;
/*
* signal synchronous inactive transactions unless this
* is a synchronous mount filesystem in which case we
* know that we're here because we've been called out of
* xfs_inactive which means that the last reference is gone
* and the unlink transaction has already hit the disk so
* async inactive transactions are safe.
* Signal synchronous inactive transactions unless this is a
* synchronous mount filesystem in which case we know that we're here
* because we've been called out of xfs_inactive which means that the
* last reference is gone and the unlink transaction has already hit
* the disk so async inactive transactions are safe.
*/
if ((error = xfs_itruncate_finish(&trans, dp, 0LL, XFS_ATTR_FORK,
(!(mp->m_flags & XFS_MOUNT_WSYNC)
? 1 : 0))))
if (!(mp->m_flags & XFS_MOUNT_WSYNC)) {
if (dp->i_d.di_anextents > 0)
xfs_trans_set_sync(trans);
}
error = xfs_itruncate_extents(&trans, dp, XFS_ATTR_FORK, 0);
if (error)
goto out;
/*

357
fs/xfs/xfs_inode.c
View file

@ -52,7 +52,7 @@ kmem_zone_t *xfs_ifork_zone;
kmem_zone_t *xfs_inode_zone;
/*
* Used in xfs_itruncate(). This is the maximum number of extents
* Used in xfs_itruncate_extents(). This is the maximum number of extents
* freed from a file in a single transaction.
*/
#define XFS_ITRUNC_MAX_EXTENTS 2
@ -1179,15 +1179,15 @@ xfs_ialloc(
* at least do it for regular files.
*/
#ifdef DEBUG
void
STATIC void
xfs_isize_check(
xfs_mount_t *mp,
xfs_inode_t *ip,
xfs_fsize_t isize)
struct xfs_inode *ip,
xfs_fsize_t isize)
{
xfs_fileoff_t map_first;
int nimaps;
xfs_bmbt_irec_t imaps[2];
struct xfs_mount *mp = ip->i_mount;
xfs_fileoff_t map_first;
int nimaps;
xfs_bmbt_irec_t imaps[2];
if ((ip->i_d.di_mode & S_IFMT) != S_IFREG)
return;
@ -1214,11 +1214,14 @@ xfs_isize_check(
ASSERT(nimaps == 1);
ASSERT(imaps[0].br_startblock == HOLESTARTBLOCK);
}
#else /* DEBUG */
#define xfs_isize_check(ip, isize)
#endif /* DEBUG */
/*
* Free up the underlying blocks past new_size. The new size must be
* smaller than the current size.
* Free up the underlying blocks past new_size. The new size must be smaller
* than the current size. This routine can be used both for the attribute and
* data fork, and does not modify the inode size, which is left to the caller.
*
* The transaction passed to this routine must have made a permanent log
* reservation of at least XFS_ITRUNCATE_LOG_RES. This routine may commit the
@ -1230,31 +1233,6 @@ xfs_isize_check(
* will be "held" within the returned transaction. This routine does NOT
* require any disk space to be reserved for it within the transaction.
*
* The fork parameter must be either XFS_ATTR_FORK or XFS_DATA_FORK, and it
* indicates the fork which is to be truncated. For the attribute fork we only
* support truncation to size 0.
*
* We use the sync parameter to indicate whether or not the first transaction
* we perform might have to be synchronous. For the attr fork, it needs to be
* so if the unlink of the inode is not yet known to be permanent in the log.
* This keeps us from freeing and reusing the blocks of the attribute fork
* before the unlink of the inode becomes permanent.
*
* For the data fork, we normally have to run synchronously if we're being
* called out of the inactive path or we're being called out of the create path
* where we're truncating an existing file. Either way, the truncate needs to
* be sync so blocks don't reappear in the file with altered data in case of a
* crash. wsync filesystems can run the first case async because anything that
* shrinks the inode has to run sync so by the time we're called here from
* inactive, the inode size is permanently set to 0.
*
* Calls from the truncate path always need to be sync unless we're in a wsync
* filesystem and the file has already been unlinked.
*
* The caller is responsible for correctly setting the sync parameter. It gets
* too hard for us to guess here which path we're being called out of just
* based on inode state.
*
* If we get an error, we must return with the inode locked and linked into the
* current transaction. This keeps things simple for the higher level code,
* because it always knows that the inode is locked and held in the transaction
@ -1262,124 +1240,31 @@ xfs_isize_check(
* dirty on error so that transactions can be easily aborted if possible.
*/
int
xfs_itruncate_finish(
xfs_trans_t **tp,
xfs_inode_t *ip,
xfs_fsize_t new_size,
int fork,
int sync)
xfs_itruncate_extents(
struct xfs_trans **tpp,
struct xfs_inode *ip,
int whichfork,
xfs_fsize_t new_size)
{
xfs_fsblock_t first_block;
xfs_fileoff_t first_unmap_block;
xfs_fileoff_t last_block;
xfs_filblks_t unmap_len=0;
xfs_mount_t *mp;
xfs_trans_t *ntp;
int done;
int committed;
xfs_bmap_free_t free_list;
int error;
struct xfs_mount *mp = ip->i_mount;
struct xfs_trans *tp = *tpp;
struct xfs_trans *ntp;
xfs_bmap_free_t free_list;
xfs_fsblock_t first_block;
xfs_fileoff_t first_unmap_block;
xfs_fileoff_t last_block;
xfs_filblks_t unmap_len;
int committed;
int error = 0;
int done = 0;
ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL|XFS_IOLOCK_EXCL));
ASSERT((new_size == 0) || (new_size <= ip->i_size));
ASSERT(*tp != NULL);
ASSERT((*tp)->t_flags & XFS_TRANS_PERM_LOG_RES);
ASSERT(ip->i_transp == *tp);
ASSERT(new_size <= ip->i_size);
ASSERT(tp->t_flags & XFS_TRANS_PERM_LOG_RES);
ASSERT(ip->i_transp == tp);
ASSERT(ip->i_itemp != NULL);
ASSERT(ip->i_itemp->ili_lock_flags == 0);
ntp = *tp;
mp = (ntp)->t_mountp;
ASSERT(! XFS_NOT_DQATTACHED(mp, ip));
/*
* We only support truncating the entire attribute fork.
*/
if (fork == XFS_ATTR_FORK) {
new_size = 0LL;
}
first_unmap_block = XFS_B_TO_FSB(mp, (xfs_ufsize_t)new_size);
trace_xfs_itruncate_finish_start(ip, new_size);
/*
* The first thing we do is set the size to new_size permanently
* on disk. This way we don't have to worry about anyone ever
* being able to look at the data being freed even in the face
* of a crash. What we're getting around here is the case where
* we free a block, it is allocated to another file, it is written
* to, and then we crash. If the new data gets written to the
* file but the log buffers containing the free and reallocation
* don't, then we'd end up with garbage in the blocks being freed.
* As long as we make the new_size permanent before actually
* freeing any blocks it doesn't matter if they get written to.
*
* The callers must signal into us whether or not the size
* setting here must be synchronous. There are a few cases
* where it doesn't have to be synchronous. Those cases
* occur if the file is unlinked and we know the unlink is
* permanent or if the blocks being truncated are guaranteed
* to be beyond the inode eof (regardless of the link count)
* and the eof value is permanent. Both of these cases occur
* only on wsync-mounted filesystems. In those cases, we're
* guaranteed that no user will ever see the data in the blocks
* that are being truncated so the truncate can run async.
* In the free beyond eof case, the file may wind up with
* more blocks allocated to it than it needs if we crash
* and that won't get fixed until the next time the file
* is re-opened and closed but that's ok as that shouldn't
* be too many blocks.
*
* However, we can't just make all wsync xactions run async
* because there's one call out of the create path that needs
* to run sync where it's truncating an existing file to size
* 0 whose size is > 0.
*
* It's probably possible to come up with a test in this
* routine that would correctly distinguish all the above
* cases from the values of the function parameters and the
* inode state but for sanity's sake, I've decided to let the
* layers above just tell us. It's simpler to correctly figure
* out in the layer above exactly under what conditions we
* can run async and I think it's easier for others read and
* follow the logic in case something has to be changed.
* cscope is your friend -- rcc.
*
* The attribute fork is much simpler.
*
* For the attribute fork we allow the caller to tell us whether
* the unlink of the inode that led to this call is yet permanent
* in the on disk log. If it is not and we will be freeing extents
* in this inode then we make the first transaction synchronous
* to make sure that the unlink is permanent by the time we free
* the blocks.
*/
if (fork == XFS_DATA_FORK) {
if (ip->i_d.di_nextents > 0) {
/*
* If we are not changing the file size then do
* not update the on-disk file size - we may be
* called from xfs_inactive_free_eofblocks(). If we
* update the on-disk file size and then the system
* crashes before the contents of the file are
* flushed to disk then the files may be full of
* holes (ie NULL files bug).
*/
if (ip->i_size != new_size) {
ip->i_d.di_size = new_size;
ip->i_size = new_size;
xfs_trans_log_inode(ntp, ip, XFS_ILOG_CORE);
}
}
} else if (sync) {
ASSERT(!(mp->m_flags & XFS_MOUNT_WSYNC));
if (ip->i_d.di_anextents > 0)
xfs_trans_set_sync(ntp);
}
ASSERT(fork == XFS_DATA_FORK ||
(fork == XFS_ATTR_FORK &&
((sync && !(mp->m_flags & XFS_MOUNT_WSYNC)) ||
(sync == 0 && (mp->m_flags & XFS_MOUNT_WSYNC)))));
ASSERT(!XFS_NOT_DQATTACHED(mp, ip));
/*
* Since it is possible for space to become allocated beyond
@ -1390,128 +1275,142 @@ xfs_itruncate_finish(
* beyond the maximum file size (ie it is the same as last_block),
* then there is nothing to do.
*/
first_unmap_block = XFS_B_TO_FSB(mp, (xfs_ufsize_t)new_size);
last_block = XFS_B_TO_FSB(mp, (xfs_ufsize_t)XFS_MAXIOFFSET(mp));
ASSERT(first_unmap_block <= last_block);
done = 0;
if (last_block == first_unmap_block) {
done = 1;
} else {
unmap_len = last_block - first_unmap_block + 1;
}
if (first_unmap_block == last_block)
return 0;
ASSERT(first_unmap_block < last_block);
unmap_len = last_block - first_unmap_block + 1;
while (!done) {
/*
* Free up up to XFS_ITRUNC_MAX_EXTENTS. xfs_bunmapi()
* will tell us whether it freed the entire range or
* not. If this is a synchronous mount (wsync),
* then we can tell bunmapi to keep all the
* transactions asynchronous since the unlink
* transaction that made this inode inactive has
* already hit the disk. There's no danger of
* the freed blocks being reused, there being a
* crash, and the reused blocks suddenly reappearing
* in this file with garbage in them once recovery
* runs.
*/
xfs_bmap_init(&free_list, &first_block);
error = xfs_bunmapi(ntp, ip,
error = xfs_bunmapi(tp, ip,
first_unmap_block, unmap_len,
xfs_bmapi_aflag(fork),
xfs_bmapi_aflag(whichfork),
XFS_ITRUNC_MAX_EXTENTS,
&first_block, &free_list,
&done);
if (error) {
/*
* If the bunmapi call encounters an error,
* return to the caller where the transaction
* can be properly aborted. We just need to
* make sure we're not holding any resources
* that we were not when we came in.
*/
xfs_bmap_cancel(&free_list);
return error;
}
if (error)
goto out_bmap_cancel;
/*
* Duplicate the transaction that has the permanent
* reservation and commit the old transaction.
*/
error = xfs_bmap_finish(tp, &free_list, &committed);
ntp = *tp;
error = xfs_bmap_finish(&tp, &free_list, &committed);
if (committed)
xfs_trans_ijoin(ntp, ip);
if (error) {
/*
* If the bmap finish call encounters an error, return
* to the caller where the transaction can be properly
* aborted. We just need to make sure we're not
* holding any resources that we were not when we came
* in.
*
* Aborting from this point might lose some blocks in
* the file system, but oh well.
*/
xfs_bmap_cancel(&free_list);
return error;
}
xfs_trans_ijoin(tp, ip);
if (error)
goto out_bmap_cancel;
if (committed) {
/*
* Mark the inode dirty so it will be logged and
* moved forward in the log as part of every commit.
*/
xfs_trans_log_inode(ntp, ip, XFS_ILOG_CORE);
xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
}
ntp = xfs_trans_dup(ntp);
error = xfs_trans_commit(*tp, 0);
*tp = ntp;
ntp = xfs_trans_dup(tp);
error = xfs_trans_commit(tp, 0);
tp = ntp;
xfs_trans_ijoin(ntp, ip);
xfs_trans_ijoin(tp, ip);
if (error)
return error;
goto out;
/*
* transaction commit worked ok so we can drop the extra ticket
* Transaction commit worked ok so we can drop the extra ticket
* reference that we gained in xfs_trans_dup()
*/
xfs_log_ticket_put(ntp->t_ticket);
error = xfs_trans_reserve(ntp, 0,
xfs_log_ticket_put(tp->t_ticket);
error = xfs_trans_reserve(tp, 0,
XFS_ITRUNCATE_LOG_RES(mp), 0,
XFS_TRANS_PERM_LOG_RES,
XFS_ITRUNCATE_LOG_COUNT);
if (error)
return error;
goto out;
}
out:
*tpp = tp;
return error;
out_bmap_cancel:
/*
* Only update the size in the case of the data fork, but
* always re-log the inode so that our permanent transaction
* can keep on rolling it forward in the log.
* If the bunmapi call encounters an error, return to the caller where
* the transaction can be properly aborted. We just need to make sure
* we're not holding any resources that we were not when we came in.
*/
if (fork == XFS_DATA_FORK) {
xfs_isize_check(mp, ip, new_size);
xfs_bmap_cancel(&free_list);
goto out;
}
int
xfs_itruncate_data(
struct xfs_trans **tpp,
struct xfs_inode *ip,
xfs_fsize_t new_size)
{
int error;
trace_xfs_itruncate_data_start(ip, new_size);
/*
* The first thing we do is set the size to new_size permanently on
* disk. This way we don't have to worry about anyone ever being able
* to look at the data being freed even in the face of a crash.
* What we're getting around here is the case where we free a block, it
* is allocated to another file, it is written to, and then we crash.
* If the new data gets written to the file but the log buffers
* containing the free and reallocation don't, then we'd end up with
* garbage in the blocks being freed. As long as we make the new_size
* permanent before actually freeing any blocks it doesn't matter if
* they get written to.
*/
if (ip->i_d.di_nextents > 0) {
/*
* If we are not changing the file size then do
* not update the on-disk file size - we may be
* called from xfs_inactive_free_eofblocks(). If we
* update the on-disk file size and then the system
* crashes before the contents of the file are
* flushed to disk then the files may be full of
* holes (ie NULL files bug).
* If we are not changing the file size then do not update
* the on-disk file size - we may be called from
* xfs_inactive_free_eofblocks(). If we update the on-disk
* file size and then the system crashes before the contents
* of the file are flushed to disk then the files may be
* full of holes (ie NULL files bug).
*/
if (ip->i_size != new_size) {
ip->i_d.di_size = new_size;
ip->i_size = new_size;
xfs_trans_log_inode(*tpp, ip, XFS_ILOG_CORE);
}
}
xfs_trans_log_inode(ntp, ip, XFS_ILOG_CORE);
ASSERT((new_size != 0) ||
(fork == XFS_ATTR_FORK) ||
(ip->i_delayed_blks == 0));
ASSERT((new_size != 0) ||
(fork == XFS_ATTR_FORK) ||
(ip->i_d.di_nextents == 0));
trace_xfs_itruncate_finish_end(ip, new_size);
error = xfs_itruncate_extents(tpp, ip, XFS_DATA_FORK, new_size);
if (error)
return error;
/*
* If we are not changing the file size then do not update the on-disk
* file size - we may be called from xfs_inactive_free_eofblocks().
* If we update the on-disk file size and then the system crashes
* before the contents of the file are flushed to disk then the files
* may be full of holes (ie NULL files bug).
*/
xfs_isize_check(ip, new_size);
if (ip->i_size != new_size) {
ip->i_d.di_size = new_size;
ip->i_size = new_size;
}
ASSERT(new_size != 0 || ip->i_delayed_blks == 0);
ASSERT(new_size != 0 || ip->i_d.di_nextents == 0);
/*
* Always re-log the inode so that our permanent transaction can keep
* on rolling it forward in the log.
*/
xfs_trans_log_inode(*tpp, ip, XFS_ILOG_CORE);
trace_xfs_itruncate_data_end(ip, new_size);
return 0;
}

13
fs/xfs/xfs_inode.h
View file

@ -491,8 +491,10 @@ uint xfs_ip2xflags(struct xfs_inode *);
uint xfs_dic2xflags(struct xfs_dinode *);
int xfs_ifree(struct xfs_trans *, xfs_inode_t *,
struct xfs_bmap_free *);
int xfs_itruncate_finish(struct xfs_trans **, xfs_inode_t *,
xfs_fsize_t, int, int);
int xfs_itruncate_extents(struct xfs_trans **, struct xfs_inode *,
int, xfs_fsize_t);
int xfs_itruncate_data(struct xfs_trans **, struct xfs_inode *,
xfs_fsize_t);
int xfs_iunlink(struct xfs_trans *, xfs_inode_t *);
void xfs_iext_realloc(xfs_inode_t *, int, int);
@ -568,13 +570,6 @@ void xfs_iext_irec_update_extoffs(xfs_ifork_t *, int, int);
#define xfs_ipincount(ip) ((unsigned int) atomic_read(&ip->i_pincount))
#ifdef DEBUG
void xfs_isize_check(struct xfs_mount *, struct xfs_inode *,
xfs_fsize_t);
#else /* DEBUG */
#define xfs_isize_check(mp, ip, isize)
#endif /* DEBUG */
#if defined(DEBUG)
void xfs_inobp_check(struct xfs_mount *, struct xfs_buf *);
#else

24
fs/xfs/xfs_vnodeops.c
View file

@ -220,15 +220,12 @@ xfs_free_eofblocks(
xfs_ilock(ip, XFS_ILOCK_EXCL);
xfs_trans_ijoin(tp, ip);
error = xfs_itruncate_finish(&tp, ip,
ip->i_size,
XFS_DATA_FORK,
0);
/*
* If we get an error at this point we
* simply don't bother truncating the file.
*/
error = xfs_itruncate_data(&tp, ip, ip->i_size);
if (error) {
/*
* If we get an error at this point we simply don't
* bother truncating the file.
*/
xfs_trans_cancel(tp,
(XFS_TRANS_RELEASE_LOG_RES |
XFS_TRANS_ABORT));
@ -665,16 +662,7 @@ xfs_inactive(
xfs_ilock(ip, XFS_ILOCK_EXCL);
xfs_trans_ijoin(tp, ip);
/*
* normally, we have to run xfs_itruncate_finish sync.
* But if filesystem is wsync and we're in the inactive
* path, then we know that nlink == 0, and that the
* xaction that made nlink == 0 is permanently committed
* since xfs_remove runs as a synchronous transaction.
*/
error = xfs_itruncate_finish(&tp, ip, 0, XFS_DATA_FORK,
(!(mp->m_flags & XFS_MOUNT_WSYNC) ? 1 : 0));
error = xfs_itruncate_data(&tp, ip, 0);
if (error) {
xfs_trans_cancel(tp,
XFS_TRANS_RELEASE_LOG_RES | XFS_TRANS_ABORT);