4.19-stable review patch. If anyone has any objections, please let me know.
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From: Ryusuke Konishi konishi.ryusuke@gmail.com
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@gmail.com Signed-off-by: Ryusuke Konishi konishi.ryusuke@gmail.com Cc: Hillf Danton hdanton@sina.com Cc: Jan Kara jack@suse.cz Cc: Matthew Wilcox (Oracle) willy@infradead.org Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- 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(-)
--- a/fs/nilfs2/alloc.c +++ b/fs/nilfs2/alloc.c @@ -377,11 +377,12 @@ void *nilfs_palloc_block_get_entry(const * @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_s
end = target; } + if (!wrap) + return -ENOSPC;
/* wrap around */ for (pos = 0; pos < end; pos++) { @@ -495,9 +498,10 @@ int nilfs_palloc_count_max_entries(struc * 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(str 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(str 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( --- 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 *); --- a/fs/nilfs2/dat.c +++ b/fs/nilfs2/dat.c @@ -75,7 +75,7 @@ int nilfs_dat_prepare_alloc(struct inode { int ret;
- ret = nilfs_palloc_prepare_alloc_entry(dat, req); + ret = nilfs_palloc_prepare_alloc_entry(dat, req, true); if (ret < 0) return ret;
--- a/fs/nilfs2/ifile.c +++ b/fs/nilfs2/ifile.c @@ -55,13 +55,10 @@ int nilfs_ifile_create_inode(struct inod 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);