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Code Issues Releases Wiki Activity

udf: Fix lock ordering in udf_evict_inode()

Browse source 
udf_evict_inode() calls udf_setsize() to truncate deleted inode.
However inode deletion through udf_evict_inode() can happen from inode
reclaim context and udf_setsize() grabs mapping->invalidate_lock which
isn't generally safe to acquire from fs reclaim context since we
allocate pages under mapping->invalidate_lock for example in a page
fault path.  This is however not a real deadlock possibility as by the
time udf_evict_inode() is called, nobody can be accessing the inode,
even less work with its page cache. So this is just a lockdep triggering
false positive. Fix the problem by moving mapping->invalidate_lock
locking outsize of udf_setsize() into udf_setattr() as grabbing
mapping->invalidate_lock from udf_evict_inode() is pointless.

Reported-by: syzbot+0333a6f4b88bcd68a62f@syzkaller.appspotmail.com
Fixes: b9a861fd52 ("udf: Protect truncate and file type conversion with invalidate_lock")
Signed-off-by: Jan Kara <jack@suse.cz>
This commit is contained in:
Jan Kara 2024-05-20 15:23:37 +02:00
parent c1f1b25a60
commit 8832fc1e50
2 changed files with 6 additions and 7 deletions
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2
fs/udf/file.c
View file

@ -232,7 +232,9 @@ static int udf_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
if ((attr->ia_valid & ATTR_SIZE) &&
attr->ia_size != i_size_read(inode)) {
filemap_invalidate_lock(inode->i_mapping);
error = udf_setsize(inode, attr->ia_size);
filemap_invalidate_unlock(inode->i_mapping);
if (error)
return error;
}

11
fs/udf/inode.c
View file

@ -1248,7 +1248,6 @@ int udf_setsize(struct inode *inode, loff_t newsize)
S_ISLNK(inode->i_mode)))
return -EINVAL;
filemap_invalidate_lock(inode->i_mapping);
iinfo = UDF_I(inode);
if (newsize > inode->i_size) {
if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB) {
@ -1261,11 +1260,11 @@ int udf_setsize(struct inode *inode, loff_t newsize)
}
err = udf_expand_file_adinicb(inode);
if (err)
goto out_unlock;
return err;
}
err = udf_extend_file(inode, newsize);
if (err)
goto out_unlock;
return err;
set_size:
truncate_setsize(inode, newsize);
} else {
@ -1283,14 +1282,14 @@ int udf_setsize(struct inode *inode, loff_t newsize)
err = block_truncate_page(inode->i_mapping, newsize,
udf_get_block);
if (err)
goto out_unlock;
return err;
truncate_setsize(inode, newsize);
down_write(&iinfo->i_data_sem);
udf_clear_extent_cache(inode);
err = udf_truncate_extents(inode);
up_write(&iinfo->i_data_sem);
if (err)
goto out_unlock;
return err;
}
update_time:
inode_set_mtime_to_ts(inode, inode_set_ctime_current(inode));
@ -1298,8 +1297,6 @@ int udf_setsize(struct inode *inode, loff_t newsize)
udf_sync_inode(inode);
else
mark_inode_dirty(inode);
out_unlock:
filemap_invalidate_unlock(inode->i_mapping);
return err;
}