[PATCH 2/4] btrfs: put initial index value of a directory in a constant
From: fdmanana@kernel.org
Date: 2021-12-15 12:20:11
Subsystem:
btrfs file system, filesystems (vfs and infrastructure), the rest · Maintainers:
Chris Mason, David Sterba, Alexander Viro, Christian Brauner, Linus Torvalds
From: Filipe Manana <redacted> At btrfs_set_inode_index_count() we refer twice to the number 2 as the initial index value for a directory (when it's empty), with a proper comment explaining the reason for that value. In the next patch I'll have to use that magic value in the directory logging code, so put the value in a #define at btrfs_inode.h, to avoid hardcoding the magic value again at tree-log.c. Signed-off-by: Filipe Manana <redacted> --- fs/btrfs/btrfs_inode.h | 12 ++++++++++-- fs/btrfs/inode.c | 10 ++-------- 2 files changed, 12 insertions(+), 10 deletions(-)
diff --git a/fs/btrfs/btrfs_inode.h b/fs/btrfs/btrfs_inode.h
index b3e46aabc3d8..6d4f42b0fdce 100644
--- a/fs/btrfs/btrfs_inode.h
+++ b/fs/btrfs/btrfs_inode.h@@ -13,6 +13,13 @@ #include "ordered-data.h" #include "delayed-inode.h" +/* + * Since we search a directory based on f_pos (struct dir_context::pos) we have + * to start at 2 since '.' and '..' have f_pos of 0 and 1 respectively, so + * everybody else has to start at 2 (see btrfs_real_readdir() and dir_emit_dots()). + */ +#define BTRFS_DIR_START_INDEX 2 + /* * ordered_data_close is set by truncate when a file that used * to have good data has been truncated to zero. When it is set
@@ -173,8 +180,9 @@ struct btrfs_inode { u64 disk_i_size; /* - * if this is a directory then index_cnt is the counter for the index - * number for new files that are created + * If this is a directory then index_cnt is the counter for the index + * number for new files that are created. For an empty directory, this + * must be initialized to BTRFS_DIR_START_INDEX. */ u64 index_cnt;
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index a88130c7782e..97fd33d599eb 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c@@ -5971,14 +5971,8 @@ static int btrfs_set_inode_index_count(struct btrfs_inode *inode) goto out; ret = 0; - /* - * MAGIC NUMBER EXPLANATION: - * since we search a directory based on f_pos we have to start at 2 - * since '.' and '..' have f_pos of 0 and 1 respectively, so everybody - * else has to start at 2 - */ if (path->slots[0] == 0) { - inode->index_cnt = 2; + inode->index_cnt = BTRFS_DIR_START_INDEX; goto out; }
@@ -5989,7 +5983,7 @@ static int btrfs_set_inode_index_count(struct btrfs_inode *inode) if (found_key.objectid != btrfs_ino(inode) || found_key.type != BTRFS_DIR_INDEX_KEY) { - inode->index_cnt = 2; + inode->index_cnt = BTRFS_DIR_START_INDEX; goto out; }
--
2.33.0