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author | Christoph Hellwig <hch@lst.de> | 2011-07-08 14:34:34 +0200 |
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committer | Christoph Hellwig <hch@lst.de> | 2011-07-08 14:34:34 +0200 |
commit | 8f04c47aa9712874af2c8816c2ca2a332cba80e4 (patch) | |
tree | 56f76e7d1443759ed68c6720e7f242950e220f8c /fs/xfs/xfs_inode.c | |
parent | 857b9778d86ccba7d7b42c9d8aeecde794ec8a6b (diff) | |
download | blackbird-op-linux-8f04c47aa9712874af2c8816c2ca2a332cba80e4.tar.gz blackbird-op-linux-8f04c47aa9712874af2c8816c2ca2a332cba80e4.zip |
xfs: split xfs_itruncate_finish
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>
Diffstat (limited to 'fs/xfs/xfs_inode.c')
-rw-r--r-- | fs/xfs/xfs_inode.c | 357 |
1 files changed, 128 insertions, 229 deletions
diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c index 82a282ab63dc..aa143b870afb 100644 --- a/fs/xfs/xfs_inode.c +++ b/fs/xfs/xfs_inode.c @@ -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; } |