[XFS] Make hole punching at EOF atomic.
If hole punching at EOF is done as two steps (i.e. truncate then extend) the file is in a transient state between the two steps where an application can see the incorrect file size. Punching a hole to EOF needs to be treated in teh same way as all other hole punching cases so that the file size is never seen to change. SGI-PV: 962012 SGI-Modid: xfs-linux-melb:xfs-kern:28641a Signed-off-by: David Chinner <dgc@sgi.com> Signed-off-by: Vlad Apostolov <vapo@sgi.com> Signed-off-by: Tim Shimmin <tes@sgi.com>
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@ -71,6 +71,12 @@ xfs_fsb_to_db_io(struct xfs_iocore *io, xfs_fsblock_t fsb)
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XFS_FSB_TO_DADDR((io)->io_mount, (fsb)));
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}
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/*
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* Flags for xfs_free_eofblocks
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*/
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#define XFS_FREE_EOF_LOCK (1<<0)
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#define XFS_FREE_EOF_NOLOCK (1<<1)
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/*
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* Prototypes for functions in xfs_rw.c.
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*/
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@ -96,5 +102,7 @@ extern int xfs_change_file_space(bhv_desc_t *bdp, int cmd, xfs_flock64_t *bf,
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xfs_off_t offset, cred_t *credp, int flags);
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extern int xfs_set_dmattrs(bhv_desc_t *bdp, u_int evmask, u_int16_t state,
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cred_t *credp);
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extern int xfs_free_eofblocks(struct xfs_mount *mp, struct xfs_inode *ip,
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int flags);
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#endif /* __XFS_RW_H__ */
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@ -1201,13 +1201,15 @@ xfs_fsync(
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}
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/*
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* This is called by xfs_inactive to free any blocks beyond eof,
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* when the link count isn't zero.
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* This is called by xfs_inactive to free any blocks beyond eof
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* when the link count isn't zero and by xfs_dm_punch_hole() when
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* punching a hole to EOF.
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*/
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STATIC int
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xfs_inactive_free_eofblocks(
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int
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xfs_free_eofblocks(
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xfs_mount_t *mp,
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xfs_inode_t *ip)
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xfs_inode_t *ip,
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int flags)
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{
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xfs_trans_t *tp;
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int error;
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@ -1216,6 +1218,7 @@ xfs_inactive_free_eofblocks(
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xfs_filblks_t map_len;
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int nimaps;
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xfs_bmbt_irec_t imap;
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int use_iolock = (flags & XFS_FREE_EOF_LOCK);
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/*
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* Figure out if there are any blocks beyond the end
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@ -1256,10 +1259,12 @@ xfs_inactive_free_eofblocks(
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* cache and we can't
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* do that within a transaction.
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*/
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if (use_iolock)
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xfs_ilock(ip, XFS_IOLOCK_EXCL);
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error = xfs_itruncate_start(ip, XFS_ITRUNC_DEFINITE,
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ip->i_size);
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if (error) {
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if (use_iolock)
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xfs_iunlock(ip, XFS_IOLOCK_EXCL);
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return error;
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}
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@ -1297,7 +1302,8 @@ xfs_inactive_free_eofblocks(
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error = xfs_trans_commit(tp,
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XFS_TRANS_RELEASE_LOG_RES);
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}
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xfs_iunlock(ip, XFS_IOLOCK_EXCL | XFS_ILOCK_EXCL);
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xfs_iunlock(ip, (use_iolock ? (XFS_IOLOCK_EXCL|XFS_ILOCK_EXCL)
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: XFS_ILOCK_EXCL));
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}
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return error;
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}
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@ -1573,7 +1579,8 @@ xfs_release(
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(ip->i_df.if_flags & XFS_IFEXTENTS)) &&
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(!(ip->i_d.di_flags &
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(XFS_DIFLAG_PREALLOC | XFS_DIFLAG_APPEND)))) {
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if ((error = xfs_inactive_free_eofblocks(mp, ip)))
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error = xfs_free_eofblocks(mp, ip, XFS_FREE_EOF_LOCK);
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if (error)
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return error;
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/* Update linux inode block count after free above */
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vn_to_inode(vp)->i_blocks = XFS_FSB_TO_BB(mp,
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@ -1654,7 +1661,8 @@ xfs_inactive(
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(!(ip->i_d.di_flags &
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(XFS_DIFLAG_PREALLOC | XFS_DIFLAG_APPEND)) ||
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(ip->i_delayed_blks != 0)))) {
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if ((error = xfs_inactive_free_eofblocks(mp, ip)))
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error = xfs_free_eofblocks(mp, ip, XFS_FREE_EOF_LOCK);
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if (error)
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return VN_INACTIVE_CACHE;
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/* Update linux inode block count after free above */
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vn_to_inode(vp)->i_blocks = XFS_FSB_TO_BB(mp,
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