In fs/ext4/super.c, the function ext4_nfs_get_inode takes as input "generation" that can be used to specify the generation of the inode to be returned. When 0 is given as input, then inodes of any generation can be returned. Therefore, generation 0 is a special case that should be avoided when assigning generation to inodes.
A new inline function, ext4_inode_set_gen, will take care of the problem. Now, inodes cannot have a generation of 0, so this patch fixes the issue. Signed-off-by: Kyungchan Koh <[email protected]> --- fs/ext4/ext4.h | 8 ++++++++ fs/ext4/ialloc.c | 2 +- fs/ext4/ioctl.c | 4 ++-- 3 files changed, 11 insertions(+), 3 deletions(-) diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index 3219154..74c6677 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -1549,6 +1549,14 @@ static inline int ext4_valid_inum(struct super_block *sb, unsigned long ino) ino <= le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count)); } +static inline void ext4_inode_set_gen(struct inode *inode, + struct ext4_sb_info *sbi) +{ + inode->i_generation = sbi->s_next_generation++; + if (!inode->i_generation) + inode->i_generation = sbi->s_next_generation++; +} + /* * Inode dynamic state flags */ diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c index 98ac2f1..d33f6f0 100644 --- a/fs/ext4/ialloc.c +++ b/fs/ext4/ialloc.c @@ -1072,7 +1072,7 @@ struct inode *__ext4_new_inode(handle_t *handle, struct inode *dir, goto out; } spin_lock(&sbi->s_next_gen_lock); - inode->i_generation = sbi->s_next_generation++; + ext4_inode_set_gen(inode, sbi); spin_unlock(&sbi->s_next_gen_lock); /* Precompute checksum seed for inode metadata */ diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c index 0c21e22..d52a467 100644 --- a/fs/ext4/ioctl.c +++ b/fs/ext4/ioctl.c @@ -160,8 +160,8 @@ static long swap_inode_boot_loader(struct super_block *sb, inode->i_ctime = inode_bl->i_ctime = current_time(inode); spin_lock(&sbi->s_next_gen_lock); - inode->i_generation = sbi->s_next_generation++; - inode_bl->i_generation = sbi->s_next_generation++; + ext4_inode_set_gen(inode, sbi); + ext4_inode_set_gen(inode_bl, sbi); spin_unlock(&sbi->s_next_gen_lock); ext4_discard_preallocations(inode); -- 2.9.3
