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 <chandan@linux.vnet.ibm.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index a9496644f47d3e8b89fbefc5de4faf041f838120..ffb3617fad98b16a12537bac0c1b8c5db11e2819 100644 (file)
--- 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 af782fdd4fcab60acf638ebec752dd205d5d998c..9809557213d49b89d73686ead0c11803fd37f779 100644 (file)
--- 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,