The following commits were cherry-picked from upstream to fix a crash in ext4/054. There was a minor fix-up needed in the first patch, although no other changes were needed for the 2nd and 3rd patches.
Ext4/054 will cause older LTS kernels to crash, but unfortunately these patches will need further back-porting to apply to 5.4, never mind older LTS kernels. But at least here are the fixes for 5.10....
Zhang Yi (3): ext4: prevent partial update of the extent blocks ext4: check for out-of-order index extents in ext4_valid_extent_entries() ext4: check for inconsistent extents between index and leaf block
fs/ext4/extents.c | 93 ++++++++++++++++++++++++++++++++--------------- 1 file changed, 63 insertions(+), 30 deletions(-)
From: Zhang Yi yi.zhang@huawei.com
Commit 0f2f87d51aebcf71a709b52f661d681594c7dffa upstream.
In the most error path of current extents updating operations are not roll back partial updates properly when some bad things happens(.e.g in ext4_ext_insert_extent()). So we may get an inconsistent extents tree if journal has been aborted due to IO error, which may probability lead to BUGON later when we accessing these extent entries in errors=continue mode. This patch drop extent buffer's verify flag before updatng the contents in ext4_ext_get_access(), and reset it after updating in __ext4_ext_dirty(). After this patch we could force to check the extent buffer if extents tree updating was break off, make sure the extents are consistent.
Signed-off-by: Zhang Yi yi.zhang@huawei.com Reviewed-by: Theodore Ts'o tytso@mit.edu Link: https://lore.kernel.org/r/20210908120850.4012324-4-yi.zhang@huawei.com Signed-off-by: Theodore Ts'o tytso@mit.edu --- fs/ext4/extents.c | 17 +++++++++++++++-- 1 file changed, 15 insertions(+), 2 deletions(-)
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c index aa4d74f9d162..f2e569e9701d 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -136,14 +136,24 @@ int ext4_datasem_ensure_credits(handle_t *handle, struct inode *inode, static int ext4_ext_get_access(handle_t *handle, struct inode *inode, struct ext4_ext_path *path) { + int err = 0; + if (path->p_bh) { /* path points to block */ BUFFER_TRACE(path->p_bh, "get_write_access"); - return ext4_journal_get_write_access(handle, path->p_bh); + err = ext4_journal_get_write_access(handle, path->p_bh); + /* + * The extent buffer's verified bit will be set again in + * __ext4_ext_dirty(). We could leave an inconsistent + * buffer if the extents updating procudure break off du + * to some error happens, force to check it again. + */ + if (!err) + clear_buffer_verified(path->p_bh); } /* path points to leaf/index in inode body */ /* we use in-core data, no need to protect them */ - return 0; + return err; }
/* @@ -164,6 +174,9 @@ static int __ext4_ext_dirty(const char *where, unsigned int line, /* path points to block */ err = __ext4_handle_dirty_metadata(where, line, handle, inode, path->p_bh); + /* Extents updating done, re-set verified flag */ + if (!err) + set_buffer_verified(path->p_bh); } else { /* path points to leaf/index in inode body */ err = ext4_mark_inode_dirty(handle, inode);
From: Zhang Yi yi.zhang@huawei.com
Commit 8dd27fecede55e8a4e67eef2878040ecad0f0d33 upstream.
After commit 5946d089379a ("ext4: check for overlapping extents in ext4_valid_extent_entries()"), we can check out the overlapping extent entry in leaf extent blocks. But the out-of-order extent entry in index extent blocks could also trigger bad things if the filesystem is inconsistent. So this patch add a check to figure out the out-of-order index extents and return error.
Signed-off-by: Zhang Yi yi.zhang@huawei.com Reviewed-by: Theodore Ts'o tytso@mit.edu Link: https://lore.kernel.org/r/20210908120850.4012324-2-yi.zhang@huawei.com Signed-off-by: Theodore Ts'o tytso@mit.edu --- fs/ext4/extents.c | 17 ++++++++++++----- 1 file changed, 12 insertions(+), 5 deletions(-)
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c index f2e569e9701d..35648dc3ff50 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -369,6 +369,9 @@ static int ext4_valid_extent_entries(struct inode *inode, ext4_fsblk_t *pblk, int depth) { unsigned short entries; + ext4_lblk_t lblock = 0; + ext4_lblk_t prev = 0; + if (eh->eh_entries == 0) return 1;
@@ -377,31 +380,35 @@ static int ext4_valid_extent_entries(struct inode *inode, if (depth == 0) { /* leaf entries */ struct ext4_extent *ext = EXT_FIRST_EXTENT(eh); - ext4_lblk_t lblock = 0; - ext4_lblk_t prev = 0; - int len = 0; while (entries) { if (!ext4_valid_extent(inode, ext)) return 0;
/* Check for overlapping extents */ lblock = le32_to_cpu(ext->ee_block); - len = ext4_ext_get_actual_len(ext); if ((lblock <= prev) && prev) { *pblk = ext4_ext_pblock(ext); return 0; } + prev = lblock + ext4_ext_get_actual_len(ext) - 1; ext++; entries--; - prev = lblock + len - 1; } } else { struct ext4_extent_idx *ext_idx = EXT_FIRST_INDEX(eh); while (entries) { if (!ext4_valid_extent_idx(inode, ext_idx)) return 0; + + /* Check for overlapping index extents */ + lblock = le32_to_cpu(ext_idx->ei_block); + if ((lblock <= prev) && prev) { + *pblk = ext4_idx_pblock(ext_idx); + return 0; + } ext_idx++; entries--; + prev = lblock; } } return 1;
From: Zhang Yi yi.zhang@huawei.com
Now that we can check out overlapping extents in leaf block and out-of-order index extents in index block. But the .ee_block in the first extent of one leaf block should equal to the .ei_block in it's parent index extent entry. This patch add a check to verify such inconsistent between the index and leaf block.
Commit 9c6e071913792d80894cd0be98cc3c4b770e26d3 upstream.
Signed-off-by: Zhang Yi yi.zhang@huawei.com Link: https://lore.kernel.org/r/20210908120850.4012324-3-yi.zhang@huawei.com Signed-off-by: Theodore Ts'o tytso@mit.edu --- fs/ext4/extents.c | 59 +++++++++++++++++++++++++++++------------------ 1 file changed, 36 insertions(+), 23 deletions(-)
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c index 35648dc3ff50..618675a41efb 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -366,7 +366,8 @@ static int ext4_valid_extent_idx(struct inode *inode,
static int ext4_valid_extent_entries(struct inode *inode, struct ext4_extent_header *eh, - ext4_fsblk_t *pblk, int depth) + ext4_lblk_t lblk, ext4_fsblk_t *pblk, + int depth) { unsigned short entries; ext4_lblk_t lblock = 0; @@ -380,6 +381,14 @@ static int ext4_valid_extent_entries(struct inode *inode, if (depth == 0) { /* leaf entries */ struct ext4_extent *ext = EXT_FIRST_EXTENT(eh); + + /* + * The logical block in the first entry should equal to + * the number in the index block. + */ + if (depth != ext_depth(inode) && + lblk != le32_to_cpu(ext->ee_block)) + return 0; while (entries) { if (!ext4_valid_extent(inode, ext)) return 0; @@ -396,6 +405,14 @@ static int ext4_valid_extent_entries(struct inode *inode, } } else { struct ext4_extent_idx *ext_idx = EXT_FIRST_INDEX(eh); + + /* + * The logical block in the first entry should equal to + * the number in the parent index block. + */ + if (depth != ext_depth(inode) && + lblk != le32_to_cpu(ext_idx->ei_block)) + return 0; while (entries) { if (!ext4_valid_extent_idx(inode, ext_idx)) return 0; @@ -416,7 +433,7 @@ static int ext4_valid_extent_entries(struct inode *inode,
static int __ext4_ext_check(const char *function, unsigned int line, struct inode *inode, struct ext4_extent_header *eh, - int depth, ext4_fsblk_t pblk) + int depth, ext4_fsblk_t pblk, ext4_lblk_t lblk) { const char *error_msg; int max = 0, err = -EFSCORRUPTED; @@ -442,7 +459,7 @@ static int __ext4_ext_check(const char *function, unsigned int line, error_msg = "invalid eh_entries"; goto corrupted; } - if (!ext4_valid_extent_entries(inode, eh, &pblk, depth)) { + if (!ext4_valid_extent_entries(inode, eh, lblk, &pblk, depth)) { error_msg = "invalid extent entries"; goto corrupted; } @@ -472,7 +489,7 @@ static int __ext4_ext_check(const char *function, unsigned int line, }
#define ext4_ext_check(inode, eh, depth, pblk) \ - __ext4_ext_check(__func__, __LINE__, (inode), (eh), (depth), (pblk)) + __ext4_ext_check(__func__, __LINE__, (inode), (eh), (depth), (pblk), 0)
int ext4_ext_check_inode(struct inode *inode) { @@ -505,16 +522,18 @@ static void ext4_cache_extents(struct inode *inode,
static struct buffer_head * __read_extent_tree_block(const char *function, unsigned int line, - struct inode *inode, ext4_fsblk_t pblk, int depth, - int flags) + struct inode *inode, struct ext4_extent_idx *idx, + int depth, int flags) { struct buffer_head *bh; int err; gfp_t gfp_flags = __GFP_MOVABLE | GFP_NOFS; + ext4_fsblk_t pblk;
if (flags & EXT4_EX_NOFAIL) gfp_flags |= __GFP_NOFAIL;
+ pblk = ext4_idx_pblock(idx); bh = sb_getblk_gfp(inode->i_sb, pblk, gfp_flags); if (unlikely(!bh)) return ERR_PTR(-ENOMEM); @@ -527,8 +546,8 @@ __read_extent_tree_block(const char *function, unsigned int line, } if (buffer_verified(bh) && !(flags & EXT4_EX_FORCE_CACHE)) return bh; - err = __ext4_ext_check(function, line, inode, - ext_block_hdr(bh), depth, pblk); + err = __ext4_ext_check(function, line, inode, ext_block_hdr(bh), + depth, pblk, le32_to_cpu(idx->ei_block)); if (err) goto errout; set_buffer_verified(bh); @@ -546,8 +565,8 @@ __read_extent_tree_block(const char *function, unsigned int line,
}
-#define read_extent_tree_block(inode, pblk, depth, flags) \ - __read_extent_tree_block(__func__, __LINE__, (inode), (pblk), \ +#define read_extent_tree_block(inode, idx, depth, flags) \ + __read_extent_tree_block(__func__, __LINE__, (inode), (idx), \ (depth), (flags))
/* @@ -597,8 +616,7 @@ int ext4_ext_precache(struct inode *inode) i--; continue; } - bh = read_extent_tree_block(inode, - ext4_idx_pblock(path[i].p_idx++), + bh = read_extent_tree_block(inode, path[i].p_idx++, depth - i - 1, EXT4_EX_FORCE_CACHE); if (IS_ERR(bh)) { @@ -903,8 +921,7 @@ ext4_find_extent(struct inode *inode, ext4_lblk_t block, path[ppos].p_depth = i; path[ppos].p_ext = NULL;
- bh = read_extent_tree_block(inode, path[ppos].p_block, --i, - flags); + bh = read_extent_tree_block(inode, path[ppos].p_idx, --i, flags); if (IS_ERR(bh)) { ret = PTR_ERR(bh); goto err; @@ -1509,7 +1526,6 @@ static int ext4_ext_search_right(struct inode *inode, struct ext4_extent_header *eh; struct ext4_extent_idx *ix; struct ext4_extent *ex; - ext4_fsblk_t block; int depth; /* Note, NOT eh_depth; depth from top of tree */ int ee_len;
@@ -1576,20 +1592,17 @@ static int ext4_ext_search_right(struct inode *inode, * follow it and find the closest allocated * block to the right */ ix++; - block = ext4_idx_pblock(ix); while (++depth < path->p_depth) { /* subtract from p_depth to get proper eh_depth */ - bh = read_extent_tree_block(inode, block, - path->p_depth - depth, 0); + bh = read_extent_tree_block(inode, ix, path->p_depth - depth, 0); if (IS_ERR(bh)) return PTR_ERR(bh); eh = ext_block_hdr(bh); ix = EXT_FIRST_INDEX(eh); - block = ext4_idx_pblock(ix); put_bh(bh); }
- bh = read_extent_tree_block(inode, block, path->p_depth - depth, 0); + bh = read_extent_tree_block(inode, ix, path->p_depth - depth, 0); if (IS_ERR(bh)) return PTR_ERR(bh); eh = ext_block_hdr(bh); @@ -2968,9 +2981,9 @@ int ext4_ext_remove_space(struct inode *inode, ext4_lblk_t start, ext_debug(inode, "move to level %d (block %llu)\n", i + 1, ext4_idx_pblock(path[i].p_idx)); memset(path + i + 1, 0, sizeof(*path)); - bh = read_extent_tree_block(inode, - ext4_idx_pblock(path[i].p_idx), depth - i - 1, - EXT4_EX_NOCACHE); + bh = read_extent_tree_block(inode, path[i].p_idx, + depth - i - 1, + EXT4_EX_NOCACHE); if (IS_ERR(bh)) { /* should we reset i_size? */ err = PTR_ERR(bh);
On Mon, Dec 20, 2021 at 10:36:56AM -0500, Theodore Ts'o wrote:
The following commits were cherry-picked from upstream to fix a crash in ext4/054. There was a minor fix-up needed in the first patch, although no other changes were needed for the 2nd and 3rd patches.
Ext4/054 will cause older LTS kernels to crash, but unfortunately these patches will need further back-porting to apply to 5.4, never mind older LTS kernels. But at least here are the fixes for 5.10....
Zhang Yi (3): ext4: prevent partial update of the extent blocks ext4: check for out-of-order index extents in ext4_valid_extent_entries() ext4: check for inconsistent extents between index and leaf block
fs/ext4/extents.c | 93 ++++++++++++++++++++++++++++++++--------------- 1 file changed, 63 insertions(+), 30 deletions(-)
-- 2.31.0
I also had to apply them to 5.15.y as you do not want people to upgrade and have a regression.
thanks,
greg k-h
linux-stable-mirror@lists.linaro.org
-
Greg KH -
Theodore Ts'o