From: Artem Bityutskiy <artem.bityutskiy@xxxxxxxxxxxxxxx>
This patch changes the 'i_nlink' counter handling in 'ubifs_unlink()',
'ubifs_rmdir()' and 'ubifs_rename()'. In these function 'i_nlink' may become 0,
and if 'ubifs_jnl_update()' failed, we would use 'inc_nlink()' to restore
the previous 'i_nlink' value, which is incorrect from the VFS point of view and
would cause a 'WARN_ON()' (see 'inc_nlink() implementation).
This patches saves the previous 'i_nlink' value in a local variable and uses it
at the error path instead of calling 'inc_nlink()'. We do this only for the
inodes where 'i_nlink' may potentially become zero.
This change has been requested by Al Viro <viro@xxxxxxxxxxxxxxxxxx>.
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@xxxxxxxxxxxxxxx>
---
Al, I assume this goes in via the UBIFS tree.
fs/ubifs/dir.c | 18 +++++++++---------
1 files changed, 9 insertions(+), 9 deletions(-)
diff --git a/fs/ubifs/dir.c b/fs/ubifs/dir.c
index d6fe1c7..ec9f187 100644
--- a/fs/ubifs/dir.c
+++ b/fs/ubifs/dir.c
@@ -566,6 +566,7 @@ static int ubifs_unlink(struct inode *dir, struct dentry *dentry)
int sz_change = CALC_DENT_SIZE(dentry->d_name.len);
int err, budgeted = 1;
struct ubifs_budget_req req = { .mod_dent = 1, .dirtied_ino = 2 };
+ unsigned int saved_nlink = inode->i_nlink;
/*
* Budget request settings: deletion direntry, deletion inode (+1 for
@@ -613,7 +614,7 @@ static int ubifs_unlink(struct inode *dir, struct dentry *dentry)
out_cancel:
dir->i_size += sz_change;
dir_ui->ui_size = dir->i_size;
- inc_nlink(inode);
+ set_nlink(inode, saved_nlink);
unlock_2_inodes(dir, inode);
if (budgeted)
ubifs_release_budget(c, &req);
@@ -704,8 +705,7 @@ out_cancel:
dir->i_size += sz_change;
dir_ui->ui_size = dir->i_size;
inc_nlink(dir);
- inc_nlink(inode);
- inc_nlink(inode);
+ set_nlink(inode, 2);
unlock_2_inodes(dir, inode);
if (budgeted)
ubifs_release_budget(c, &req);
@@ -977,6 +977,7 @@ static int ubifs_rename(struct inode *old_dir, struct dentry *old_dentry,
struct ubifs_budget_req ino_req = { .dirtied_ino = 1,
.dirtied_ino_d = ALIGN(old_inode_ui->data_len, 8) };
struct timespec time;
+ unsigned int saved_nlink;
/*
* Budget request settings: deletion direntry, new direntry, removing
@@ -1059,13 +1060,14 @@ static int ubifs_rename(struct inode *old_dir, struct dentry *old_dentry,
if (unlink) {
/*
* Directories cannot have hard-links, so if this is a
- * directory, decrement its @i_nlink twice because an empty
- * directory has @i_nlink 2.
+ * directory, just clear @i_nlink.
*/
+ saved_nlink = new_inode->i_nlink;
if (is_dir)
+ clear_nlink(new_inode);
+ else
drop_nlink(new_inode);
new_inode->i_ctime = time;
- drop_nlink(new_inode);
} else {
new_dir->i_size += new_sz;
ubifs_inode(new_dir)->ui_size = new_dir->i_size;
@@ -1102,9 +1104,7 @@ static int ubifs_rename(struct inode *old_dir, struct dentry *old_dentry,
out_cancel:
if (unlink) {
- if (is_dir)
- inc_nlink(new_inode);
- inc_nlink(new_inode);
+ set_nlink(new_inode, saved_nlink);
} else {
new_dir->i_size -= new_sz;
ubifs_inode(new_dir)->ui_size = new_dir->i_size;
--
1.7.7.6
--
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