From 2e78c927d79333f299a8ac81c2fd2952caeef335 Mon Sep 17 00:00:00 2001 From: Chandan Rajendra Date: Thu, 21 Jan 2016 15:55:53 +0530 Subject: [PATCH] Btrfs: __btrfs_buffered_write: Reserve/release extents aligned to block size Currently, the code reserves/releases extents in multiples of PAGE_CACHE_SIZE units. Fix this by doing reservation/releases in block size units. Signed-off-by: Chandan Rajendra Signed-off-by: David Sterba --- fs/btrfs/ctree.h | 3 +++ fs/btrfs/file.c | 43 ++++++++++++++++++++++++++++++------------- 2 files changed, 33 insertions(+), 13 deletions(-) diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index a9496644f47d..ffb3617fad98 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -2353,6 +2353,9 @@ struct btrfs_map_token { unsigned long offset; }; +#define BTRFS_BYTES_TO_BLKS(fs_info, bytes) \ + ((bytes) >> (fs_info)->sb->s_blocksize_bits) + static inline void btrfs_init_map_token (struct btrfs_map_token *token) { token->kaddr = NULL; diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c index af782fdd4fca..9809557213d4 100644 --- a/fs/btrfs/file.c +++ b/fs/btrfs/file.c @@ -498,7 +498,7 @@ int btrfs_dirty_pages(struct btrfs_root *root, struct inode *inode, loff_t isize = i_size_read(inode); start_pos = pos & ~((u64)root->sectorsize - 1); - num_bytes = ALIGN(write_bytes + pos - start_pos, root->sectorsize); + num_bytes = round_up(write_bytes + pos - start_pos, root->sectorsize); end_of_last_block = start_pos + num_bytes - 1; err = btrfs_set_extent_delalloc(inode, start_pos, end_of_last_block, @@ -1379,16 +1379,19 @@ fail: static noinline int lock_and_cleanup_extent_if_need(struct inode *inode, struct page **pages, size_t num_pages, loff_t pos, + size_t write_bytes, u64 *lockstart, u64 *lockend, struct extent_state **cached_state) { + struct btrfs_root *root = BTRFS_I(inode)->root; u64 start_pos; u64 last_pos; int i; int ret = 0; - start_pos = pos & ~((u64)PAGE_CACHE_SIZE - 1); - last_pos = start_pos + ((u64)num_pages << PAGE_CACHE_SHIFT) - 1; + start_pos = round_down(pos, root->sectorsize); + last_pos = start_pos + + round_up(pos + write_bytes - start_pos, root->sectorsize) - 1; if (start_pos < inode->i_size) { struct btrfs_ordered_extent *ordered; @@ -1503,6 +1506,7 @@ static noinline ssize_t __btrfs_buffered_write(struct file *file, while (iov_iter_count(i) > 0) { size_t offset = pos & (PAGE_CACHE_SIZE - 1); + size_t sector_offset; size_t write_bytes = min(iov_iter_count(i), nrptrs * (size_t)PAGE_CACHE_SIZE - offset); @@ -1511,6 +1515,8 @@ static noinline ssize_t __btrfs_buffered_write(struct file *file, size_t reserve_bytes; size_t dirty_pages; size_t copied; + size_t dirty_sectors; + size_t num_sectors; WARN_ON(num_pages > nrptrs); @@ -1523,7 +1529,9 @@ static noinline ssize_t __btrfs_buffered_write(struct file *file, break; } - reserve_bytes = num_pages << PAGE_CACHE_SHIFT; + sector_offset = pos & (root->sectorsize - 1); + reserve_bytes = round_up(write_bytes + sector_offset, + root->sectorsize); if (BTRFS_I(inode)->flags & (BTRFS_INODE_NODATACOW | BTRFS_INODE_PREALLOC)) { @@ -1542,7 +1550,9 @@ static noinline ssize_t __btrfs_buffered_write(struct file *file, */ num_pages = DIV_ROUND_UP(write_bytes + offset, PAGE_CACHE_SIZE); - reserve_bytes = num_pages << PAGE_CACHE_SHIFT; + reserve_bytes = round_up(write_bytes + + sector_offset, + root->sectorsize); goto reserve_metadata; } } @@ -1576,8 +1586,8 @@ again: break; ret = lock_and_cleanup_extent_if_need(inode, pages, num_pages, - pos, &lockstart, &lockend, - &cached_state); + pos, write_bytes, &lockstart, + &lockend, &cached_state); if (ret < 0) { if (ret == -EAGAIN) goto again; @@ -1612,9 +1622,16 @@ again: * we still have an outstanding extent for the chunk we actually * managed to copy. */ - if (num_pages > dirty_pages) { - release_bytes = (num_pages - dirty_pages) << - PAGE_CACHE_SHIFT; + num_sectors = BTRFS_BYTES_TO_BLKS(root->fs_info, + reserve_bytes); + dirty_sectors = round_up(copied + sector_offset, + root->sectorsize); + dirty_sectors = BTRFS_BYTES_TO_BLKS(root->fs_info, + dirty_sectors); + + if (num_sectors > dirty_sectors) { + release_bytes = (write_bytes - copied) + & ~((u64)root->sectorsize - 1); if (copied > 0) { spin_lock(&BTRFS_I(inode)->lock); BTRFS_I(inode)->outstanding_extents++; @@ -1633,7 +1650,8 @@ again: } } - release_bytes = dirty_pages << PAGE_CACHE_SHIFT; + release_bytes = round_up(copied + sector_offset, + root->sectorsize); if (copied > 0) ret = btrfs_dirty_pages(root, inode, pages, @@ -1654,8 +1672,7 @@ again: if (only_release_metadata && copied > 0) { lockstart = round_down(pos, root->sectorsize); - lockend = lockstart + - (dirty_pages << PAGE_CACHE_SHIFT) - 1; + lockend = round_up(pos + copied, root->sectorsize) - 1; set_extent_bit(&BTRFS_I(inode)->io_tree, lockstart, lockend, EXTENT_NORESERVE, NULL,