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kernel: Fix the incorrect i_nlink count after jffs2's RENAME_EXCHANGE operations.

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The problem is caused by the incorrect handling of the parent inode's
i_nlink count for the dentry to be RENAME_EXCHANGED. There are 3 cases
to consider. Assume we want to RENAME_EXCHANGE struct dentry *a and
struct dentry *b, and inode_a is pointed to by dentry_a, inode_b is
pointed to by dentry_b:

1. If inode_a is a directory, but inode_b isn't, then we must decrease
   the i_nlink count of old_dir_i, and increase the i_nlink of new_dir_i.
2. If inode_a isn't a directory, but inode_b is a directory, then we
   must increase the i_nlink of old_dir_i, and decrease the i_nlink count
   of new_dir_i.
3. If the types of inode_a and inode_b are the same, we don't change the
   i_nlink for either old_dir_i or new_dir_i.

Signed-off-by: Jing Qiu <aqiu0720@gmail.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>
This commit is contained in:
Jing Qiu 2017-03-14 15:32:08 +08:00 committed by Felix Fietkau
parent 47bf110cbb
commit 638ca50f3b
1 changed files with 28 additions and 5 deletions
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33
target/linux/generic/patches-4.4/111-jffs2-add-RENAME_EXCHANGE-support.patch
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@ -7,7 +7,12 @@ Signed-off-by: Felix Fietkau <nbd@nbd.name>
--- a/fs/jffs2/dir.c
+++ b/fs/jffs2/dir.c
@@ -782,7 +782,7 @@ static int jffs2_rename (struct inode *o
@@ -779,18 +779,31 @@ static int jffs2_rename (struct inode *o
int ret;
struct jffs2_sb_info *c = JFFS2_SB_INFO(old_dir_i->i_sb);
struct jffs2_inode_info *victim_f = NULL;
+ struct inode *fst_inode = d_inode(old_dentry);
+ struct inode *snd_inode = d_inode(new_dentry);
uint8_t type;
uint32_t now;
@ -15,8 +20,19 @@ Signed-off-by: Felix Fietkau <nbd@nbd.name>
+ if (flags & ~(RENAME_WHITEOUT | RENAME_EXCHANGE))
return -EINVAL;
+ if ((flags & RENAME_EXCHANGE) && (old_dir_i != new_dir_i)) {
+ if (S_ISDIR(fst_inode->i_mode) && !S_ISDIR(snd_inode->i_mode)) {
+ inc_nlink(new_dir_i);
+ drop_nlink(old_dir_i);
+ }
+ else if (!S_ISDIR(fst_inode->i_mode) && S_ISDIR(snd_inode->i_mode)) {
+ drop_nlink(new_dir_i);
+ inc_nlink(old_dir_i);
+ }
+ }
+
/* The VFS will check for us and prevent trying to rename a
@@ -790,7 +790,7 @@ static int jffs2_rename (struct inode *o
* file over a directory and vice versa, but if it's a directory,
* the VFS can't check whether the victim is empty. The filesystem
* needs to do that for itself.
*/
@ -25,7 +41,7 @@ Signed-off-by: Felix Fietkau <nbd@nbd.name>
victim_f = JFFS2_INODE_INFO(d_inode(new_dentry));
if (d_is_dir(new_dentry)) {
struct jffs2_full_dirent *fd;
@@ -825,7 +825,7 @@ static int jffs2_rename (struct inode *o
@@ -825,7 +838,7 @@ static int jffs2_rename (struct inode *o
if (ret)
return ret;
@ -34,7 +50,14 @@ Signed-off-by: Felix Fietkau <nbd@nbd.name>
/* There was a victim. Kill it off nicely */
if (d_is_dir(new_dentry))
clear_nlink(d_inode(new_dentry));
@@ -851,6 +851,12 @@ static int jffs2_rename (struct inode *o
@@ -845,12 +858,18 @@ static int jffs2_rename (struct inode *o
/* If it was a directory we moved, and there was no victim,
increase i_nlink on its new parent */
- if (d_is_dir(old_dentry) && !victim_f)
+ if (d_is_dir(old_dentry) && !victim_f && !(flags & RENAME_EXCHANGE))
inc_nlink(new_dir_i);
if (flags & RENAME_WHITEOUT)
/* Replace with whiteout */
ret = jffs2_whiteout(old_dir_i, old_dentry);
@ -47,7 +70,7 @@ Signed-off-by: Felix Fietkau <nbd@nbd.name>
else
/* Unlink the original */
ret = jffs2_do_unlink(c, JFFS2_INODE_INFO(old_dir_i),
@@ -882,7 +888,7 @@ static int jffs2_rename (struct inode *o
@@ -882,7 +901,7 @@ static int jffs2_rename (struct inode *o
return ret;
}