diff options
| -rw-r--r-- | fs/ext4/ext4.h | 5 | ||||
| -rw-r--r-- | fs/ext4/namei.c | 22 |
2 files changed, 16 insertions, 11 deletions
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index c902d4430..4c800e8b7 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -1835,7 +1835,10 @@ static inline __le16 ext4_rec_len_to_disk(unsigned len, unsigned blocksize) #define is_dx(dir) (EXT4_HAS_COMPAT_FEATURE(dir->i_sb, \ EXT4_FEATURE_COMPAT_DIR_INDEX) && \ ext4_test_inode_flag((dir), EXT4_INODE_INDEX)) -#define EXT4_DIR_LINK_MAX(dir) (!is_dx(dir) && (dir)->i_nlink >= EXT4_LINK_MAX) +#define EXT4_DIR_LINK_MAX(dir) unlikely((dir)->i_nlink >= EXT4_LINK_MAX && \ + !(EXT4_HAS_COMPAT_FEATURE(dir->i_sb, \ + EXT4_FEATURE_RO_COMPAT_DIR_NLINK) && \ + is_dx(dir))) #define EXT4_DIR_LINK_EMPTY(dir) ((dir)->i_nlink == 2 || (dir)->i_nlink == 1) /* Legal values for the dx_root hash_version field: */ diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c index 77c133140..e9226fd33 100644 --- a/fs/ext4/namei.c +++ b/fs/ext4/namei.c @@ -2381,20 +2381,22 @@ out: } /* - * DIR_NLINK feature is set if 1) nlinks > EXT4_LINK_MAX or 2) nlinks == 2, - * since this indicates that nlinks count was previously 1. + * Set directory link count to 1 if nlinks > EXT4_LINK_MAX, or if nlinks == 2 + * since this indicates that nlinks count was previously 1 to avoid overflowing + * the 16-bit i_links_count field on disk. Directories with i_nlink == 1 mean + * that subdirectory link counts are not being maintained accurately. + * + * The caller has already checked for i_nlink overflow in case the DIR_LINK + * feature is not enabled and returned -EMLINK. The is_dx() check is a proxy + * for checking S_ISDIR(inode) (since the INODE_INDEX feature will not be set + * on regular files) and to avoid creating huge/slow non-HTREE directories. */ static void ext4_inc_count(handle_t *handle, struct inode *inode) { inc_nlink(inode); - if (is_dx(inode) && inode->i_nlink > 1) { - /* limit is 16-bit i_links_count */ - if (inode->i_nlink >= EXT4_LINK_MAX || inode->i_nlink == 2) { - set_nlink(inode, 1); - EXT4_SET_RO_COMPAT_FEATURE(inode->i_sb, - EXT4_FEATURE_RO_COMPAT_DIR_NLINK); - } - } + if (is_dx(inode) && + (inode->i_nlink > EXT4_LINK_MAX || inode->i_nlink == 2)) + set_nlink(inode, 1); } /* |