From 638ca50f3b1d66fb165891552ed8cde31aa2f194 Mon Sep 17 00:00:00 2001 From: Jing Qiu Date: Tue, 14 Mar 2017 15:32:08 +0800 Subject: [PATCH] kernel: Fix the incorrect i_nlink count after jffs2's RENAME_EXCHANGE operations. 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 Signed-off-by: Felix Fietkau --- ...11-jffs2-add-RENAME_EXCHANGE-support.patch | 33 ++++++++++++++++--- 1 file changed, 28 insertions(+), 5 deletions(-) diff --git a/target/linux/generic/patches-4.4/111-jffs2-add-RENAME_EXCHANGE-support.patch b/target/linux/generic/patches-4.4/111-jffs2-add-RENAME_EXCHANGE-support.patch index b62408717e..37eb073df9 100644 --- a/target/linux/generic/patches-4.4/111-jffs2-add-RENAME_EXCHANGE-support.patch +++ b/target/linux/generic/patches-4.4/111-jffs2-add-RENAME_EXCHANGE-support.patch @@ -7,7 +7,12 @@ Signed-off-by: Felix Fietkau --- 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 + 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 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 /* 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 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; }