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| author | Mateusz Guzik <mjguzik@gmail.com> | 2024-06-11 15:06:24 +0300 |
|---|---|---|
| committer | Christian Brauner <brauner@kernel.org> | 2024-06-13 14:40:40 +0300 |
| commit | 5a9b911b8a24eda19eb0a5ab3b06688299a20711 (patch) | |
| tree | 9db0e22c80331e830f326295a4f8dbcdc574f2e0 /fs/inode.c | |
| parent | ddd4cd4824fa315c799174f2f655a474bf221a6c (diff) | |
| download | linux-5a9b911b8a24eda19eb0a5ab3b06688299a20711.tar.xz | |
vfs: partially sanitize i_state zeroing on inode creation
new_inode used to have the following:
spin_lock(&inode_lock);
inodes_stat.nr_inodes++;
list_add(&inode->i_list, &inode_in_use);
list_add(&inode->i_sb_list, &sb->s_inodes);
inode->i_ino = ++last_ino;
inode->i_state = 0;
spin_unlock(&inode_lock);
over time things disappeared, got moved around or got replaced (global
inode lock with a per-inode lock), eventually this got reduced to:
spin_lock(&inode->i_lock);
inode->i_state = 0;
spin_unlock(&inode->i_lock);
But the lock acquire here does not synchronize against anyone.
Additionally iget5_locked performs i_state = 0 assignment without any
locks to begin with, the two combined look confusing at best.
It looks like the current state is a leftover which was not cleaned up.
Ideally it would be an invariant that i_state == 0 to begin with, but
achieving that would require dealing with all filesystem alloc handlers
one by one.
In the meantime drop the misleading locking and move i_state zeroing to
inode_init_always so that others don't need to deal with it by hand.
Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
Link: https://lore.kernel.org/r/20240611120626.513952-3-mjguzik@gmail.com
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Diffstat (limited to 'fs/inode.c')
| -rw-r--r-- | fs/inode.c | 13 |
1 files changed, 3 insertions, 10 deletions
diff --git a/fs/inode.c b/fs/inode.c index 8c57cea7bbbb..ad7844ca92f9 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -162,6 +162,7 @@ int inode_init_always(struct super_block *sb, struct inode *inode) inode->i_sb = sb; inode->i_blkbits = sb->s_blocksize_bits; inode->i_flags = 0; + inode->i_state = 0; atomic64_set(&inode->i_sequence, 0); atomic_set(&inode->i_count, 1); inode->i_op = &empty_iops; @@ -231,6 +232,7 @@ int inode_init_always(struct super_block *sb, struct inode *inode) if (unlikely(security_inode_alloc(inode))) return -ENOMEM; + this_cpu_inc(nr_inodes); return 0; @@ -1023,14 +1025,7 @@ EXPORT_SYMBOL(get_next_ino); */ struct inode *new_inode_pseudo(struct super_block *sb) { - struct inode *inode = alloc_inode(sb); - - if (inode) { - spin_lock(&inode->i_lock); - inode->i_state = 0; - spin_unlock(&inode->i_lock); - } - return inode; + return alloc_inode(sb); } /** @@ -1254,7 +1249,6 @@ struct inode *iget5_locked(struct super_block *sb, unsigned long hashval, struct inode *new = alloc_inode(sb); if (new) { - new->i_state = 0; inode = inode_insert5(new, hashval, test, set, data); if (unlikely(inode != new)) destroy_inode(new); @@ -1297,7 +1291,6 @@ again: new = alloc_inode(sb); if (new) { - new->i_state = 0; inode = inode_insert5(new, hashval, test, set, data); if (unlikely(inode != new)) destroy_inode(new); |