From 26b91c728b2d15952432371dc2b6ba1dda1fb61f Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Mon, 18 Feb 2019 09:38:48 -0800 Subject: xfs: make COW fork unwritten extent conversions more robust If we have racing buffered and direct I/O COW fork extents under writeback can have been moved to the data fork by the time we call xfs_reflink_convert_cow from xfs_submit_ioend. This would be mostly harmless as the block numbers don't change by this move, except for the fact that xfs_bmapi_write will crash or trigger asserts when not finding existing extents, even despite trying to paper over this with the XFS_BMAPI_CONVERT_ONLY flag. Instead of special casing non-transaction conversions in the already way too complicated xfs_bmapi_write just add a new helper for the much simpler non-transactional COW fork case, which simplify ignores not found extents. Signed-off-by: Christoph Hellwig Reviewed-by: Darrick J. Wong Signed-off-by: Darrick J. Wong --- fs/xfs/libxfs/xfs_bmap.c | 9 +++---- fs/xfs/libxfs/xfs_bmap.h | 8 +++---- fs/xfs/xfs_reflink.c | 61 ++++++++++++++++++++++++++++++------------------ 3 files changed, 45 insertions(+), 33 deletions(-) (limited to 'fs/xfs') diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c index e4f29ebdf4d2..48502cb9990f 100644 --- a/fs/xfs/libxfs/xfs_bmap.c +++ b/fs/xfs/libxfs/xfs_bmap.c @@ -2031,7 +2031,7 @@ done: /* * Convert an unwritten allocation to a real allocation or vice versa. */ -STATIC int /* error */ +int /* error */ xfs_bmap_add_extent_unwritten_real( struct xfs_trans *tp, xfs_inode_t *ip, /* incore inode pointer */ @@ -4276,9 +4276,7 @@ xfs_bmapi_write( ASSERT(*nmap >= 1); ASSERT(*nmap <= XFS_BMAP_MAX_NMAP); - ASSERT(tp != NULL || - (flags & (XFS_BMAPI_CONVERT | XFS_BMAPI_COWFORK)) == - (XFS_BMAPI_CONVERT | XFS_BMAPI_COWFORK)); + ASSERT(tp != NULL); ASSERT(len > 0); ASSERT(XFS_IFORK_FORMAT(ip, whichfork) != XFS_DINODE_FMT_LOCAL); ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL)); @@ -4352,8 +4350,7 @@ xfs_bmapi_write( * First, deal with the hole before the allocated space * that we found, if any. */ - if ((need_alloc || wasdelay) && - !(flags & XFS_BMAPI_CONVERT_ONLY)) { + if (need_alloc || wasdelay) { bma.eof = eof; bma.conv = !!(flags & XFS_BMAPI_CONVERT); bma.wasdel = wasdelay; diff --git a/fs/xfs/libxfs/xfs_bmap.h b/fs/xfs/libxfs/xfs_bmap.h index 78b190b6e908..8f597f9abdbe 100644 --- a/fs/xfs/libxfs/xfs_bmap.h +++ b/fs/xfs/libxfs/xfs_bmap.h @@ -95,9 +95,6 @@ struct xfs_extent_free_item /* Map something in the CoW fork. */ #define XFS_BMAPI_COWFORK 0x200 -/* Only convert unwritten extents, don't allocate new blocks */ -#define XFS_BMAPI_CONVERT_ONLY 0x800 - /* Skip online discard of freed extents */ #define XFS_BMAPI_NODISCARD 0x1000 @@ -114,7 +111,6 @@ struct xfs_extent_free_item { XFS_BMAPI_ZERO, "ZERO" }, \ { XFS_BMAPI_REMAP, "REMAP" }, \ { XFS_BMAPI_COWFORK, "COWFORK" }, \ - { XFS_BMAPI_CONVERT_ONLY, "CONVERT_ONLY" }, \ { XFS_BMAPI_NODISCARD, "NODISCARD" }, \ { XFS_BMAPI_NORMAP, "NORMAP" } @@ -226,6 +222,10 @@ int xfs_bmapi_reserve_delalloc(struct xfs_inode *ip, int whichfork, int xfs_bmapi_convert_delalloc(struct xfs_inode *ip, int whichfork, xfs_fileoff_t offset_fsb, struct xfs_bmbt_irec *imap, unsigned int *seq); +int xfs_bmap_add_extent_unwritten_real(struct xfs_trans *tp, + struct xfs_inode *ip, int whichfork, + struct xfs_iext_cursor *icur, struct xfs_btree_cur **curp, + struct xfs_bmbt_irec *new, int *logflagsp); static inline void xfs_bmap_add_free( diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c index 9ef1f79cb3ae..f84b37fa4f17 100644 --- a/fs/xfs/xfs_reflink.c +++ b/fs/xfs/xfs_reflink.c @@ -234,26 +234,42 @@ xfs_reflink_trim_around_shared( } } -/* Convert part of an unwritten CoW extent to a real one. */ -STATIC int -xfs_reflink_convert_cow_extent( - struct xfs_inode *ip, - struct xfs_bmbt_irec *imap, - xfs_fileoff_t offset_fsb, - xfs_filblks_t count_fsb) +static int +xfs_reflink_convert_cow_locked( + struct xfs_inode *ip, + xfs_fileoff_t offset_fsb, + xfs_filblks_t count_fsb) { - int nimaps = 1; + struct xfs_iext_cursor icur; + struct xfs_bmbt_irec got; + struct xfs_btree_cur *dummy_cur = NULL; + int dummy_logflags; + int error; - if (imap->br_state == XFS_EXT_NORM) + if (!xfs_iext_lookup_extent(ip, ip->i_cowfp, offset_fsb, &icur, &got)) return 0; - xfs_trim_extent(imap, offset_fsb, count_fsb); - trace_xfs_reflink_convert_cow(ip, imap); - if (imap->br_blockcount == 0) - return 0; - return xfs_bmapi_write(NULL, ip, imap->br_startoff, imap->br_blockcount, - XFS_BMAPI_COWFORK | XFS_BMAPI_CONVERT, 0, imap, - &nimaps); + do { + if (got.br_startoff >= offset_fsb + count_fsb) + break; + if (got.br_state == XFS_EXT_NORM) + continue; + if (WARN_ON_ONCE(isnullstartblock(got.br_startblock))) + return -EIO; + + xfs_trim_extent(&got, offset_fsb, count_fsb); + if (!got.br_blockcount) + continue; + + got.br_state = XFS_EXT_NORM; + error = xfs_bmap_add_extent_unwritten_real(NULL, ip, + XFS_COW_FORK, &icur, &dummy_cur, &got, + &dummy_logflags); + if (error) + return error; + } while (xfs_iext_next_extent(ip->i_cowfp, &icur, &got)); + + return error; } /* Convert all of the unwritten CoW extents in a file's range to real ones. */ @@ -267,15 +283,12 @@ xfs_reflink_convert_cow( xfs_fileoff_t offset_fsb = XFS_B_TO_FSBT(mp, offset); xfs_fileoff_t end_fsb = XFS_B_TO_FSB(mp, offset + count); xfs_filblks_t count_fsb = end_fsb - offset_fsb; - struct xfs_bmbt_irec imap; - int nimaps = 1, error = 0; + int error; ASSERT(count != 0); xfs_ilock(ip, XFS_ILOCK_EXCL); - error = xfs_bmapi_write(NULL, ip, offset_fsb, count_fsb, - XFS_BMAPI_COWFORK | XFS_BMAPI_CONVERT | - XFS_BMAPI_CONVERT_ONLY, 0, &imap, &nimaps); + error = xfs_reflink_convert_cow_locked(ip, offset_fsb, count_fsb); xfs_iunlock(ip, XFS_ILOCK_EXCL); return error; } @@ -405,14 +418,16 @@ xfs_reflink_allocate_cow( if (nimaps == 0) return -ENOSPC; convert: + xfs_trim_extent(imap, offset_fsb, count_fsb); /* * COW fork extents are supposed to remain unwritten until we're ready * to initiate a disk write. For direct I/O we are going to write the * data and need the conversion, but for buffered writes we're done. */ - if (!(iomap_flags & IOMAP_DIRECT)) + if (!(iomap_flags & IOMAP_DIRECT) || imap->br_state == XFS_EXT_NORM) return 0; - return xfs_reflink_convert_cow_extent(ip, imap, offset_fsb, count_fsb); + trace_xfs_reflink_convert_cow(ip, imap); + return xfs_reflink_convert_cow_locked(ip, offset_fsb, count_fsb); out_unreserve: xfs_trans_unreserve_quota_nblks(tp, ip, (long)resblks, 0, -- cgit