commit 93aef9eda1cea9e84ab2453fcceb8addad0e46f1 upstream.
If the bitmap block that manages the inode allocation status is corrupted,
nilfs_ifile_create_inode() may allocate a new inode from the reserved
inode area where it should not be allocated.
Previous fix commit d325dc6eb763 ("nilfs2: fix use-after-free bug of
struct nilfs_root"), fixed the problem that reserved inodes with inode
numbers less than NILFS_USER_INO (=11) were incorrectly reallocated due to
bitmap corruption, but since the start number of non-reserved inodes is
read from the super block and may change, in which case inode allocation
may occur from the extended reserved inode area.
If that happens, access to that inode will cause an IO error, causing the
file system to degrade to an error state.
Fix this potential issue by adding a wraparound option to the common
metadata object allocation routine and by modifying
nilfs_ifile_create_inode() to disable the option so that it only allocates
inodes with inode numbers greater than or equal to the inode number read
in "nilfs->ns_first_ino", regardless of the bitmap status of reserved
inodes.
Link: https://lkml.kernel.org/r/20240623051135.4180-4-konishi.ryusuke@xxxxxxxxx
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@xxxxxxxxx>
Cc: Hillf Danton <hdanton@xxxxxxxx>
Cc: Jan Kara <jack@xxxxxxx>
Cc: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
Please apply this patch to the stable trees indicated by the subject
prefix instead of the patch that failed.
This patch is tailored to avoid conflicts with a series involving
extensive conversions and can be applied from v4.8 to v6.8.
Also, all the builds and tests I did on each stable tree passed.
Thanks,
Ryusuke Konishi
fs/nilfs2/alloc.c | 18 ++++++++++++++----
fs/nilfs2/alloc.h | 4 ++--
fs/nilfs2/dat.c | 2 +-
fs/nilfs2/ifile.c | 7 ++-----
4 files changed, 19 insertions(+), 12 deletions(-)
diff --git a/fs/nilfs2/alloc.c b/fs/nilfs2/alloc.c
index 7342de296ec3..25881bdd212b 100644
--- a/fs/nilfs2/alloc.c
+++ b/fs/nilfs2/alloc.c
@@ -377,11 +377,12 @@ void *nilfs_palloc_block_get_entry(const struct inode *inode, __u64 nr,
* @target: offset number of an entry in the group (start point)
* @bsize: size in bits
* @lock: spin lock protecting @bitmap
+ * @wrap: whether to wrap around
*/
static int nilfs_palloc_find_available_slot(unsigned char *bitmap,
unsigned long target,
unsigned int bsize,
- spinlock_t *lock)
+ spinlock_t *lock, bool wrap)
{
int pos, end = bsize;
@@ -397,6 +398,8 @@ static int nilfs_palloc_find_available_slot(unsigned char *bitmap,
end = target;
}
+ if (!wrap)
+ return -ENOSPC;
/* wrap around */
for (pos = 0; pos < end; pos++) {
@@ -495,9 +498,10 @@ int nilfs_palloc_count_max_entries(struct inode *inode, u64 nused, u64 *nmaxp)
* nilfs_palloc_prepare_alloc_entry - prepare to allocate a persistent object
* @inode: inode of metadata file using this allocator
* @req: nilfs_palloc_req structure exchanged for the allocation
+ * @wrap: whether to wrap around
*/
int nilfs_palloc_prepare_alloc_entry(struct inode *inode,
- struct nilfs_palloc_req *req)
+ struct nilfs_palloc_req *req, bool wrap)
{
struct buffer_head *desc_bh, *bitmap_bh;
struct nilfs_palloc_group_desc *desc;
@@ -516,7 +520,7 @@ int nilfs_palloc_prepare_alloc_entry(struct inode *inode,
entries_per_group = nilfs_palloc_entries_per_group(inode);
for (i = 0; i < ngroups; i += n) {
- if (group >= ngroups) {
+ if (group >= ngroups && wrap) {
/* wrap around */
group = 0;
maxgroup = nilfs_palloc_group(inode, req->pr_entry_nr,
@@ -541,7 +545,13 @@ int nilfs_palloc_prepare_alloc_entry(struct inode *inode,
bitmap = bitmap_kaddr + bh_offset(bitmap_bh);
pos = nilfs_palloc_find_available_slot(
bitmap, group_offset,
- entries_per_group, lock);
+ entries_per_group, lock, wrap);
+ /*
+ * Since the search for a free slot in the
+ * second and subsequent bitmap blocks always
+ * starts from the beginning, the wrap flag
+ * only has an effect on the first search.
+ */
if (pos >= 0) {
/* found a free entry */
nilfs_palloc_group_desc_add_entries(
diff --git a/fs/nilfs2/alloc.h b/fs/nilfs2/alloc.h
index b667e869ac07..d825a9faca6d 100644
--- a/fs/nilfs2/alloc.h
+++ b/fs/nilfs2/alloc.h
@@ -50,8 +50,8 @@ struct nilfs_palloc_req {
struct buffer_head *pr_entry_bh;
};
-int nilfs_palloc_prepare_alloc_entry(struct inode *,
- struct nilfs_palloc_req *);
+int nilfs_palloc_prepare_alloc_entry(struct inode *inode,
+ struct nilfs_palloc_req *req, bool wrap);
void nilfs_palloc_commit_alloc_entry(struct inode *,
struct nilfs_palloc_req *);
void nilfs_palloc_abort_alloc_entry(struct inode *, struct nilfs_palloc_req *);
diff --git a/fs/nilfs2/dat.c b/fs/nilfs2/dat.c
index 9cf6ba58f585..351010828d88 100644
--- a/fs/nilfs2/dat.c
+++ b/fs/nilfs2/dat.c
@@ -75,7 +75,7 @@ int nilfs_dat_prepare_alloc(struct inode *dat, struct nilfs_palloc_req *req)
{
int ret;
- ret = nilfs_palloc_prepare_alloc_entry(dat, req);
+ ret = nilfs_palloc_prepare_alloc_entry(dat, req, true);
if (ret < 0)
return ret;
diff --git a/fs/nilfs2/ifile.c b/fs/nilfs2/ifile.c
index a8a4bc8490b4..ac10a62a41e9 100644
--- a/fs/nilfs2/ifile.c
+++ b/fs/nilfs2/ifile.c
@@ -55,13 +55,10 @@ int nilfs_ifile_create_inode(struct inode *ifile, ino_t *out_ino,
struct nilfs_palloc_req req;
int ret;
- req.pr_entry_nr = 0; /*
- * 0 says find free inode from beginning
- * of a group. dull code!!
- */
+ req.pr_entry_nr = NILFS_FIRST_INO(ifile->i_sb);
req.pr_entry_bh = NULL;
- ret = nilfs_palloc_prepare_alloc_entry(ifile, &req);
+ ret = nilfs_palloc_prepare_alloc_entry(ifile, &req, false);
if (!ret) {
ret = nilfs_palloc_get_entry_block(ifile, req.pr_entry_nr, 1,
&req.pr_entry_bh);
--
2.43.5
