diff --git a/Documentation/filesystems/iomap/operations.rst b/Documentation/filesystems/iomap/operations.rst index 8e6c721d2330..b93115ab8748 100644 --- a/Documentation/filesystems/iomap/operations.rst +++ b/Documentation/filesystems/iomap/operations.rst @@ -208,7 +208,7 @@ The filesystem must arrange to `cancel such `reservations `_ because writeback will not consume the reservation. -The ``iomap_file_buffered_write_punch_delalloc`` can be called from a +The ``iomap_write_delalloc_release`` can be called from a ``->iomap_end`` function to find all the clean areas of the folios caching a fresh (``IOMAP_F_NEW``) delalloc mapping. It takes the ``invalidate_lock``. diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c index 78ebd265f425..aa587b2142e2 100644 --- a/fs/iomap/buffered-io.c +++ b/fs/iomap/buffered-io.c @@ -1145,10 +1145,36 @@ static void iomap_write_delalloc_scan(struct inode *inode, } /* + * When a short write occurs, the filesystem might need to use ->iomap_end + * to remove space reservations created in ->iomap_begin. + * + * For filesystems that use delayed allocation, there can be dirty pages over + * the delalloc extent outside the range of a short write but still within the + * delalloc extent allocated for this iomap if the write raced with page + * faults. + * * Punch out all the delalloc blocks in the range given except for those that * have dirty data still pending in the page cache - those are going to be * written and so must still retain the delalloc backing for writeback. * + * The punch() callback *must* only punch delalloc extents in the range passed + * to it. It must skip over all other types of extents in the range and leave + * them completely unchanged. It must do this punch atomically with respect to + * other extent modifications. + * + * The punch() callback may be called with a folio locked to prevent writeback + * extent allocation racing at the edge of the range we are currently punching. + * The locked folio may or may not cover the range being punched, so it is not + * safe for the punch() callback to lock folios itself. + * + * Lock order is: + * + * inode->i_rwsem (shared or exclusive) + * inode->i_mapping->invalidate_lock (exclusive) + * folio_lock() + * ->punch + * internal filesystem allocation lock + * * As we are scanning the page cache for data, we don't need to reimplement the * wheel - mapping_seek_hole_data() does exactly what we need to identify the * start and end of data ranges correctly even for sub-folio block sizes. This @@ -1177,7 +1203,7 @@ static void iomap_write_delalloc_scan(struct inode *inode, * require sprinkling this code with magic "+ 1" and "- 1" arithmetic and expose * the code to subtle off-by-one bugs.... */ -static void iomap_write_delalloc_release(struct inode *inode, loff_t start_byte, +void iomap_write_delalloc_release(struct inode *inode, loff_t start_byte, loff_t end_byte, unsigned flags, struct iomap *iomap, iomap_punch_t punch) { @@ -1185,12 +1211,13 @@ static void iomap_write_delalloc_release(struct inode *inode, loff_t start_byte, loff_t scan_end_byte = min(i_size_read(inode), end_byte); /* - * Lock the mapping to avoid races with page faults re-instantiating - * folios and dirtying them via ->page_mkwrite whilst we walk the - * cache and perform delalloc extent removal. Failing to do this can - * leave dirty pages with no space reservation in the cache. + * The caller must hold invalidate_lock to avoid races with page faults + * re-instantiating folios and dirtying them via ->page_mkwrite whilst + * we walk the cache and perform delalloc extent removal. Failing to do + * this can leave dirty pages with no space reservation in the cache. */ - filemap_invalidate_lock(inode->i_mapping); + lockdep_assert_held_write(&inode->i_mapping->invalidate_lock); + while (start_byte < scan_end_byte) { loff_t data_end; @@ -1207,7 +1234,7 @@ static void iomap_write_delalloc_release(struct inode *inode, loff_t start_byte, if (start_byte == -ENXIO || start_byte == scan_end_byte) break; if (WARN_ON_ONCE(start_byte < 0)) - goto out_unlock; + return; WARN_ON_ONCE(start_byte < punch_start_byte); WARN_ON_ONCE(start_byte > scan_end_byte); @@ -1218,7 +1245,7 @@ static void iomap_write_delalloc_release(struct inode *inode, loff_t start_byte, data_end = mapping_seek_hole_data(inode->i_mapping, start_byte, scan_end_byte, SEEK_HOLE); if (WARN_ON_ONCE(data_end < 0)) - goto out_unlock; + return; /* * If we race with post-direct I/O invalidation of the page cache, @@ -1240,74 +1267,8 @@ static void iomap_write_delalloc_release(struct inode *inode, loff_t start_byte, if (punch_start_byte < end_byte) punch(inode, punch_start_byte, end_byte - punch_start_byte, iomap); -out_unlock: - filemap_invalidate_unlock(inode->i_mapping); } - -/* - * When a short write occurs, the filesystem may need to remove reserved space - * that was allocated in ->iomap_begin from it's ->iomap_end method. For - * filesystems that use delayed allocation, we need to punch out delalloc - * extents from the range that are not dirty in the page cache. As the write can - * race with page faults, there can be dirty pages over the delalloc extent - * outside the range of a short write but still within the delalloc extent - * allocated for this iomap. - * - * This function uses [start_byte, end_byte) intervals (i.e. open ended) to - * simplify range iterations. - * - * The punch() callback *must* only punch delalloc extents in the range passed - * to it. It must skip over all other types of extents in the range and leave - * them completely unchanged. It must do this punch atomically with respect to - * other extent modifications. - * - * The punch() callback may be called with a folio locked to prevent writeback - * extent allocation racing at the edge of the range we are currently punching. - * The locked folio may or may not cover the range being punched, so it is not - * safe for the punch() callback to lock folios itself. - * - * Lock order is: - * - * inode->i_rwsem (shared or exclusive) - * inode->i_mapping->invalidate_lock (exclusive) - * folio_lock() - * ->punch - * internal filesystem allocation lock - */ -void iomap_file_buffered_write_punch_delalloc(struct inode *inode, - loff_t pos, loff_t length, ssize_t written, unsigned flags, - struct iomap *iomap, iomap_punch_t punch) -{ - loff_t start_byte; - loff_t end_byte; - unsigned int blocksize = i_blocksize(inode); - - if (iomap->type != IOMAP_DELALLOC) - return; - - /* If we didn't reserve the blocks, we're not allowed to punch them. */ - if (!(iomap->flags & IOMAP_F_NEW)) - return; - - /* - * start_byte refers to the first unused block after a short write. If - * nothing was written, round offset down to point at the first block in - * the range. - */ - if (unlikely(!written)) - start_byte = round_down(pos, blocksize); - else - start_byte = round_up(pos + written, blocksize); - end_byte = round_up(pos + length, blocksize); - - /* Nothing to do if we've written the entire delalloc extent */ - if (start_byte >= end_byte) - return; - - iomap_write_delalloc_release(inode, start_byte, end_byte, flags, iomap, - punch); -} -EXPORT_SYMBOL_GPL(iomap_file_buffered_write_punch_delalloc); +EXPORT_SYMBOL_GPL(iomap_write_delalloc_release); static loff_t iomap_unshare_iter(struct iomap_iter *iter) { diff --git a/fs/xfs/scrub/bmap_repair.c b/fs/xfs/scrub/bmap_repair.c index 49dc38acc66b..4505f4829d53 100644 --- a/fs/xfs/scrub/bmap_repair.c +++ b/fs/xfs/scrub/bmap_repair.c @@ -801,7 +801,7 @@ xrep_bmap( { struct xrep_bmap *rb; char *descr; - unsigned int max_bmbt_recs; + xfs_extnum_t max_bmbt_recs; bool large_extcount; int error = 0; diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c index 6dead20338e2..559a3a577097 100644 --- a/fs/xfs/xfs_aops.c +++ b/fs/xfs/xfs_aops.c @@ -116,7 +116,7 @@ xfs_end_ioend( if (unlikely(error)) { if (ioend->io_flags & IOMAP_F_SHARED) { xfs_reflink_cancel_cow_range(ip, offset, size, true); - xfs_bmap_punch_delalloc_range(ip, offset, + xfs_bmap_punch_delalloc_range(ip, XFS_DATA_FORK, offset, offset + size); } goto done; @@ -456,7 +456,7 @@ xfs_discard_folio( * byte of the next folio. Hence the end offset is only dependent on the * folio itself and not the start offset that is passed in. */ - xfs_bmap_punch_delalloc_range(ip, pos, + xfs_bmap_punch_delalloc_range(ip, XFS_DATA_FORK, pos, folio_pos(folio) + folio_size(folio)); } diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c index 053d567c9108..4719ec90029c 100644 --- a/fs/xfs/xfs_bmap_util.c +++ b/fs/xfs/xfs_bmap_util.c @@ -442,11 +442,12 @@ out_unlock_iolock: void xfs_bmap_punch_delalloc_range( struct xfs_inode *ip, + int whichfork, xfs_off_t start_byte, xfs_off_t end_byte) { struct xfs_mount *mp = ip->i_mount; - struct xfs_ifork *ifp = &ip->i_df; + struct xfs_ifork *ifp = xfs_ifork_ptr(ip, whichfork); xfs_fileoff_t start_fsb = XFS_B_TO_FSBT(mp, start_byte); xfs_fileoff_t end_fsb = XFS_B_TO_FSB(mp, end_byte); struct xfs_bmbt_irec got, del; @@ -474,11 +475,14 @@ xfs_bmap_punch_delalloc_range( continue; } - xfs_bmap_del_extent_delay(ip, XFS_DATA_FORK, &icur, &got, &del); + xfs_bmap_del_extent_delay(ip, whichfork, &icur, &got, &del); if (!xfs_iext_get_extent(ifp, &icur, &got)) break; } + if (whichfork == XFS_COW_FORK && !ifp->if_bytes) + xfs_inode_clear_cowblocks_tag(ip); + out_unlock: xfs_iunlock(ip, XFS_ILOCK_EXCL); } @@ -580,7 +584,7 @@ xfs_free_eofblocks( */ if (ip->i_diflags & (XFS_DIFLAG_PREALLOC | XFS_DIFLAG_APPEND)) { if (ip->i_delayed_blks) { - xfs_bmap_punch_delalloc_range(ip, + xfs_bmap_punch_delalloc_range(ip, XFS_DATA_FORK, round_up(XFS_ISIZE(ip), mp->m_sb.sb_blocksize), LLONG_MAX); } diff --git a/fs/xfs/xfs_bmap_util.h b/fs/xfs/xfs_bmap_util.h index eb0895bfb9da..b29760d36e1a 100644 --- a/fs/xfs/xfs_bmap_util.h +++ b/fs/xfs/xfs_bmap_util.h @@ -30,7 +30,7 @@ xfs_bmap_rtalloc(struct xfs_bmalloca *ap) } #endif /* CONFIG_XFS_RT */ -void xfs_bmap_punch_delalloc_range(struct xfs_inode *ip, +void xfs_bmap_punch_delalloc_range(struct xfs_inode *ip, int whichfork, xfs_off_t start_byte, xfs_off_t end_byte); struct kgetbmap { diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c index 412b1d71b52b..b19916b11fd5 100644 --- a/fs/xfs/xfs_file.c +++ b/fs/xfs/xfs_file.c @@ -347,10 +347,83 @@ xfs_file_splice_read( return ret; } +/* + * Take care of zeroing post-EOF blocks when they might exist. + * + * Returns 0 if successfully, a negative error for a failure, or 1 if this + * function dropped the iolock and reacquired it exclusively and the caller + * needs to restart the write sanity checks. + */ +static ssize_t +xfs_file_write_zero_eof( + struct kiocb *iocb, + struct iov_iter *from, + unsigned int *iolock, + size_t count, + bool *drained_dio) +{ + struct xfs_inode *ip = XFS_I(iocb->ki_filp->f_mapping->host); + loff_t isize; + int error; + + /* + * We need to serialise against EOF updates that occur in IO completions + * here. We want to make sure that nobody is changing the size while + * we do this check until we have placed an IO barrier (i.e. hold + * XFS_IOLOCK_EXCL) that prevents new IO from being dispatched. The + * spinlock effectively forms a memory barrier once we have + * XFS_IOLOCK_EXCL so we are guaranteed to see the latest EOF value and + * hence be able to correctly determine if we need to run zeroing. + */ + spin_lock(&ip->i_flags_lock); + isize = i_size_read(VFS_I(ip)); + if (iocb->ki_pos <= isize) { + spin_unlock(&ip->i_flags_lock); + return 0; + } + spin_unlock(&ip->i_flags_lock); + + if (iocb->ki_flags & IOCB_NOWAIT) + return -EAGAIN; + + if (!*drained_dio) { + /* + * If zeroing is needed and we are currently holding the iolock + * shared, we need to update it to exclusive which implies + * having to redo all checks before. + */ + if (*iolock == XFS_IOLOCK_SHARED) { + xfs_iunlock(ip, *iolock); + *iolock = XFS_IOLOCK_EXCL; + xfs_ilock(ip, *iolock); + iov_iter_reexpand(from, count); + } + + /* + * We now have an IO submission barrier in place, but AIO can do + * EOF updates during IO completion and hence we now need to + * wait for all of them to drain. Non-AIO DIO will have drained + * before we are given the XFS_IOLOCK_EXCL, and so for most + * cases this wait is a no-op. + */ + inode_dio_wait(VFS_I(ip)); + *drained_dio = true; + return 1; + } + + trace_xfs_zero_eof(ip, isize, iocb->ki_pos - isize); + + xfs_ilock(ip, XFS_MMAPLOCK_EXCL); + error = xfs_zero_range(ip, isize, iocb->ki_pos - isize, NULL); + xfs_iunlock(ip, XFS_MMAPLOCK_EXCL); + + return error; +} + /* * Common pre-write limit and setup checks. * - * Called with the iolocked held either shared and exclusive according to + * Called with the iolock held either shared and exclusive according to * @iolock, and returns with it held. Might upgrade the iolock to exclusive * if called for a direct write beyond i_size. */ @@ -360,13 +433,10 @@ xfs_file_write_checks( struct iov_iter *from, unsigned int *iolock) { - struct file *file = iocb->ki_filp; - struct inode *inode = file->f_mapping->host; - struct xfs_inode *ip = XFS_I(inode); - ssize_t error = 0; + struct inode *inode = iocb->ki_filp->f_mapping->host; size_t count = iov_iter_count(from); bool drained_dio = false; - loff_t isize; + ssize_t error; restart: error = generic_write_checks(iocb, from); @@ -389,7 +459,7 @@ restart: * exclusively. */ if (*iolock == XFS_IOLOCK_SHARED && !IS_NOSEC(inode)) { - xfs_iunlock(ip, *iolock); + xfs_iunlock(XFS_I(inode), *iolock); *iolock = XFS_IOLOCK_EXCL; error = xfs_ilock_iocb(iocb, *iolock); if (error) { @@ -400,64 +470,24 @@ restart: } /* - * If the offset is beyond the size of the file, we need to zero any + * If the offset is beyond the size of the file, we need to zero all * blocks that fall between the existing EOF and the start of this - * write. If zeroing is needed and we are currently holding the iolock - * shared, we need to update it to exclusive which implies having to - * redo all checks before. + * write. * - * We need to serialise against EOF updates that occur in IO completions - * here. We want to make sure that nobody is changing the size while we - * do this check until we have placed an IO barrier (i.e. hold the - * XFS_IOLOCK_EXCL) that prevents new IO from being dispatched. The - * spinlock effectively forms a memory barrier once we have the - * XFS_IOLOCK_EXCL so we are guaranteed to see the latest EOF value and - * hence be able to correctly determine if we need to run zeroing. - * - * We can do an unlocked check here safely as IO completion can only - * extend EOF. Truncate is locked out at this point, so the EOF can - * not move backwards, only forwards. Hence we only need to take the - * slow path and spin locks when we are at or beyond the current EOF. + * We can do an unlocked check for i_size here safely as I/O completion + * can only extend EOF. Truncate is locked out at this point, so the + * EOF can not move backwards, only forwards. Hence we only need to take + * the slow path when we are at or beyond the current EOF. */ - if (iocb->ki_pos <= i_size_read(inode)) - goto out; - - spin_lock(&ip->i_flags_lock); - isize = i_size_read(inode); - if (iocb->ki_pos > isize) { - spin_unlock(&ip->i_flags_lock); - - if (iocb->ki_flags & IOCB_NOWAIT) - return -EAGAIN; - - if (!drained_dio) { - if (*iolock == XFS_IOLOCK_SHARED) { - xfs_iunlock(ip, *iolock); - *iolock = XFS_IOLOCK_EXCL; - xfs_ilock(ip, *iolock); - iov_iter_reexpand(from, count); - } - /* - * We now have an IO submission barrier in place, but - * AIO can do EOF updates during IO completion and hence - * we now need to wait for all of them to drain. Non-AIO - * DIO will have drained before we are given the - * XFS_IOLOCK_EXCL, and so for most cases this wait is a - * no-op. - */ - inode_dio_wait(inode); - drained_dio = true; + if (iocb->ki_pos > i_size_read(inode)) { + error = xfs_file_write_zero_eof(iocb, from, iolock, count, + &drained_dio); + if (error == 1) goto restart; - } - - trace_xfs_zero_eof(ip, isize, iocb->ki_pos - isize); - error = xfs_zero_range(ip, isize, iocb->ki_pos - isize, NULL); if (error) return error; - } else - spin_unlock(&ip->i_flags_lock); + } -out: return kiocb_modified(iocb); } diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c index 1e11f48814c0..916531d9f83c 100644 --- a/fs/xfs/xfs_iomap.c +++ b/fs/xfs/xfs_iomap.c @@ -975,6 +975,7 @@ xfs_buffered_write_iomap_begin( int allocfork = XFS_DATA_FORK; int error = 0; unsigned int lockmode = XFS_ILOCK_EXCL; + unsigned int iomap_flags = 0; u64 seq; if (xfs_is_shutdown(mp)) @@ -1145,6 +1146,11 @@ xfs_buffered_write_iomap_begin( } } + /* + * Flag newly allocated delalloc blocks with IOMAP_F_NEW so we punch + * them out if the write happens to fail. + */ + iomap_flags |= IOMAP_F_NEW; if (allocfork == XFS_COW_FORK) { error = xfs_bmapi_reserve_delalloc(ip, allocfork, offset_fsb, end_fsb - offset_fsb, prealloc_blocks, &cmap, @@ -1162,19 +1168,11 @@ xfs_buffered_write_iomap_begin( if (error) goto out_unlock; - /* - * Flag newly allocated delalloc blocks with IOMAP_F_NEW so we punch - * them out if the write happens to fail. - */ - seq = xfs_iomap_inode_sequence(ip, IOMAP_F_NEW); - xfs_iunlock(ip, lockmode); trace_xfs_iomap_alloc(ip, offset, count, allocfork, &imap); - return xfs_bmbt_to_iomap(ip, iomap, &imap, flags, IOMAP_F_NEW, seq); - found_imap: - seq = xfs_iomap_inode_sequence(ip, 0); + seq = xfs_iomap_inode_sequence(ip, iomap_flags); xfs_iunlock(ip, lockmode); - return xfs_bmbt_to_iomap(ip, iomap, &imap, flags, 0, seq); + return xfs_bmbt_to_iomap(ip, iomap, &imap, flags, iomap_flags, seq); convert_delay: xfs_iunlock(ip, lockmode); @@ -1188,20 +1186,20 @@ convert_delay: return 0; found_cow: - seq = xfs_iomap_inode_sequence(ip, 0); if (imap.br_startoff <= offset_fsb) { - error = xfs_bmbt_to_iomap(ip, srcmap, &imap, flags, 0, seq); + error = xfs_bmbt_to_iomap(ip, srcmap, &imap, flags, 0, + xfs_iomap_inode_sequence(ip, 0)); if (error) goto out_unlock; - seq = xfs_iomap_inode_sequence(ip, IOMAP_F_SHARED); - xfs_iunlock(ip, lockmode); - return xfs_bmbt_to_iomap(ip, iomap, &cmap, flags, - IOMAP_F_SHARED, seq); + } else { + xfs_trim_extent(&cmap, offset_fsb, + imap.br_startoff - offset_fsb); } - xfs_trim_extent(&cmap, offset_fsb, imap.br_startoff - offset_fsb); + iomap_flags |= IOMAP_F_SHARED; + seq = xfs_iomap_inode_sequence(ip, iomap_flags); xfs_iunlock(ip, lockmode); - return xfs_bmbt_to_iomap(ip, iomap, &cmap, flags, 0, seq); + return xfs_bmbt_to_iomap(ip, iomap, &cmap, flags, iomap_flags, seq); out_unlock: xfs_iunlock(ip, lockmode); @@ -1215,7 +1213,10 @@ xfs_buffered_write_delalloc_punch( loff_t length, struct iomap *iomap) { - xfs_bmap_punch_delalloc_range(XFS_I(inode), offset, offset + length); + xfs_bmap_punch_delalloc_range(XFS_I(inode), + (iomap->flags & IOMAP_F_SHARED) ? + XFS_COW_FORK : XFS_DATA_FORK, + offset, offset + length); } static int @@ -1227,8 +1228,30 @@ xfs_buffered_write_iomap_end( unsigned flags, struct iomap *iomap) { - iomap_file_buffered_write_punch_delalloc(inode, offset, length, written, - flags, iomap, &xfs_buffered_write_delalloc_punch); + loff_t start_byte, end_byte; + + /* If we didn't reserve the blocks, we're not allowed to punch them. */ + if (iomap->type != IOMAP_DELALLOC || !(iomap->flags & IOMAP_F_NEW)) + return 0; + + /* Nothing to do if we've written the entire delalloc extent */ + start_byte = iomap_last_written_block(inode, offset, written); + end_byte = round_up(offset + length, i_blocksize(inode)); + if (start_byte >= end_byte) + return 0; + + /* For zeroing operations the callers already hold invalidate_lock. */ + if (flags & (IOMAP_UNSHARE | IOMAP_ZERO)) { + rwsem_assert_held_write(&inode->i_mapping->invalidate_lock); + iomap_write_delalloc_release(inode, start_byte, end_byte, flags, + iomap, xfs_buffered_write_delalloc_punch); + } else { + filemap_invalidate_lock(inode->i_mapping); + iomap_write_delalloc_release(inode, start_byte, end_byte, flags, + iomap, xfs_buffered_write_delalloc_punch); + filemap_invalidate_unlock(inode->i_mapping); + } + return 0; } @@ -1435,6 +1458,8 @@ xfs_zero_range( { struct inode *inode = VFS_I(ip); + xfs_assert_ilocked(ip, XFS_IOLOCK_EXCL | XFS_MMAPLOCK_EXCL); + if (IS_DAX(inode)) return dax_zero_range(inode, pos, len, did_zero, &xfs_dax_write_iomap_ops); diff --git a/include/linux/iomap.h b/include/linux/iomap.h index 4ad12a3c8bae..d0420e962ffd 100644 --- a/include/linux/iomap.h +++ b/include/linux/iomap.h @@ -256,6 +256,20 @@ static inline const struct iomap *iomap_iter_srcmap(const struct iomap_iter *i) return &i->iomap; } +/* + * Return the file offset for the first unchanged block after a short write. + * + * If nothing was written, round @pos down to point at the first block in + * the range, else round up to include the partially written block. + */ +static inline loff_t iomap_last_written_block(struct inode *inode, loff_t pos, + ssize_t written) +{ + if (unlikely(!written)) + return round_down(pos, i_blocksize(inode)); + return round_up(pos + written, i_blocksize(inode)); +} + ssize_t iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *from, const struct iomap_ops *ops, void *private); int iomap_read_folio(struct folio *folio, const struct iomap_ops *ops); @@ -276,9 +290,9 @@ vm_fault_t iomap_page_mkwrite(struct vm_fault *vmf, typedef void (*iomap_punch_t)(struct inode *inode, loff_t offset, loff_t length, struct iomap *iomap); -void iomap_file_buffered_write_punch_delalloc(struct inode *inode, loff_t pos, - loff_t length, ssize_t written, unsigned flag, - struct iomap *iomap, iomap_punch_t punch); +void iomap_write_delalloc_release(struct inode *inode, loff_t start_byte, + loff_t end_byte, unsigned flags, struct iomap *iomap, + iomap_punch_t punch); int iomap_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo, u64 start, u64 len, const struct iomap_ops *ops);