Bug#714974: [PATCH] jfs: avoid misuse of cookie value of 2
For the sake of those not watching
https://bugzilla.kernel.org/show_bug.cgi?id=60737
It looks like the problem is that jfs was using a cookie value of 2 for
a real directory entry, where NFSv4 expect 2 to represent "..". This
patch has so far only been lightly tested.
NFSv4 reserves cookie values 0, 1 and 2 for a rewind, and the "." and ".."
entries. jfs was using 0 and 1 for "." and "..", but 2 for a regular entry.
This patch makes jfs conform by using 1 and 2 for "." and ".." and fixes
any regular entry using the value 2.
Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com>
diff --git a/fs/jfs/jfs_dtree.c b/fs/jfs/jfs_dtree.c
index 8743ba9..93466e8 100644
--- a/fs/jfs/jfs_dtree.c
+++ b/fs/jfs/jfs_dtree.c
@@ -349,11 +349,8 @@ static u32 add_index(tid_t tid, struct inode *ip, s64 bn, int slot)
ASSERT(DO_INDEX(ip));
- if (jfs_ip->next_index < 2) {
- jfs_warn("add_index: next_index = %d. Resetting!",
- jfs_ip->next_index);
- jfs_ip->next_index = 2;
- }
+ if (jfs_ip->next_index < 3) {
+ jfs_ip->next_index = 3;
index = jfs_ip->next_index++;
@@ -2864,7 +2861,7 @@ void dtInitRoot(tid_t tid, struct inode *ip, u32 idotdot)
} else
ip->i_size = 1;
- jfs_ip->next_index = 2;
+ jfs_ip->next_index = 3;
} else
ip->i_size = IDATASIZE;
@@ -2951,7 +2948,7 @@ static void add_missing_indices(struct inode *inode, s64 bn)
for (i = 0; i < p->header.nextindex; i++) {
d = (struct ldtentry *) &p->slot[stbl[i]];
index = le32_to_cpu(d->index);
- if ((index < 2) || (index >= JFS_IP(inode)->next_index)) {
+ if ((index < 3) || (index >= JFS_IP(inode)->next_index)) {
d->index = cpu_to_le32(add_index(tid, inode, bn, i));
if (dtlck->index >= dtlck->maxcnt)
dtlck = (struct dt_lock *) txLinelock(dtlck);
@@ -3031,7 +3028,7 @@ int jfs_readdir(struct file *file, struct dir_context *ctx)
struct jfs_dirent *jfs_dirent;
int jfs_dirents;
int overflow, fix_page, page_fixed = 0;
- static int unique_pos = 2; /* If we can't fix broken index */
+ static int unique_pos = 3; /* If we can't fix broken index */
if (ctx->pos == DIREND)
return 0;
@@ -3039,15 +3036,16 @@ int jfs_readdir(struct file *file, struct dir_context *ctx)
if (DO_INDEX(ip)) {
/*
* persistent index is stored in directory entries.
- * Special cases: 0 = .
- * 1 = ..
+ * Special cases: 0 = rewind
+ * 1 = .
+ * 2 = ..
* -1 = End of directory
*/
do_index = 1;
dir_index = (u32) ctx->pos;
- if (dir_index > 1) {
+ if (dir_index > 2) {
struct dir_table_slot dirtab_slot;
if (dtEmpty(ip) ||
@@ -3090,18 +3088,18 @@ int jfs_readdir(struct file *file, struct dir_context *ctx)
return 0;
}
} else {
- if (dir_index == 0) {
+ if (dir_index < 2) {
/*
* self "."
*/
- ctx->pos = 0;
+ ctx->pos = 1;
if (!dir_emit(ctx, ".", 1, ip->i_ino, DT_DIR))
return 0;
}
/*
* parent ".."
*/
- ctx->pos = 1;
+ ctx->pos = 2;
if (!dir_emit(ctx, "..", 2, PARENT(ip), DT_DIR))
return 0;
@@ -3122,22 +3120,24 @@ int jfs_readdir(struct file *file, struct dir_context *ctx)
/*
* Legacy filesystem - OS/2 & Linux JFS < 0.3.6
*
- * pn = index = 0: First entry "."
- * pn = 0; index = 1: Second entry ".."
+ * pn = 0; index = 1: First entry "."
+ * pn = 0; index = 2: Second entry ".."
* pn > 0: Real entries, pn=1 -> leftmost page
* pn = index = -1: No more entries
*/
dtpos = ctx->pos;
- if (dtpos == 0) {
+ if (dtpos < 2) {
+ ctx->pos = 1;
/* build "." entry */
if (!dir_emit(ctx, ".", 1, ip->i_ino, DT_DIR))
return 0;
- dtoffset->index = 1;
+ dtoffset->index = 2;
ctx->pos = dtpos;
}
if (dtoffset->pn == 0) {
- if (dtoffset->index == 1) {
+ if (dtoffset->index == 2) {
+ ctx->pos = 2;
/* build ".." entry */
if (!dir_emit(ctx, "..", 2, PARENT(ip), DT_DIR))
return 0;
@@ -3210,8 +3210,12 @@ int jfs_readdir(struct file *file, struct dir_context *ctx)
* directory index for the lost+found
* directory. Rather than let it go,
* we can try to fix it.
+ *
+ * Additionally, a value of 2 used to be
+ * valid, but it didn't work well with
+ * NFSv4, so if found, we need to change it
*/
- if ((jfs_dirent->position < 2) ||
+ if ((jfs_dirent->position < 3) ||
(jfs_dirent->position >=
JFS_IP(ip)->next_index)) {
if (!page_fixed && !isReadOnly(ip)) {
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