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btrfs: do not double complete bio on errors during compressed reads

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I hit some weird panics while fixing up the error handling from
btrfs_lookup_bio_sums().  Turns out the compression path will complete
the bio we use if we set up any of the compression bios and then return
an error, and then btrfs_submit_data_bio() will also call bio_endio() on
the bio.

Fix this by making btrfs_submit_compressed_read() responsible for
calling bio_endio() on the bio if there are any errors.  Currently it
was only doing it if we created the compression bios, otherwise it was
depending on btrfs_submit_data_bio() to do the right thing.  This
creates the above problem, so fix up btrfs_submit_compressed_read() to
always call bio_endio() in case of an error, and then simply return from
btrfs_submit_data_bio() if we had to call
btrfs_submit_compressed_read().

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Josef Bacik 2022-02-18 10:03:27 -05:00 committed by David Sterba
parent 606f82e797
commit f9f15de85d
2 changed files with 21 additions and 7 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

20
fs/btrfs/compression.c
View file

@ -811,7 +811,7 @@ blk_status_t btrfs_submit_compressed_read(struct inode *inode, struct bio *bio,
u64 em_len; u64 em_len;
u64 em_start; u64 em_start;
struct extent_map *em; struct extent_map *em;
blk_status_t ret = BLK_STS_RESOURCE; blk_status_t ret;
int faili = 0; int faili = 0;
u8 *sums; u8 *sums;
@ -824,14 +824,18 @@ blk_status_t btrfs_submit_compressed_read(struct inode *inode, struct bio *bio,
read_lock(&em_tree->lock); read_lock(&em_tree->lock);
em = lookup_extent_mapping(em_tree, file_offset, fs_info->sectorsize); em = lookup_extent_mapping(em_tree, file_offset, fs_info->sectorsize);
read_unlock(&em_tree->lock); read_unlock(&em_tree->lock);
if (!em) if (!em) {
return BLK_STS_IOERR; ret = BLK_STS_IOERR;
goto out;
}
ASSERT(em->compress_type != BTRFS_COMPRESS_NONE); ASSERT(em->compress_type != BTRFS_COMPRESS_NONE);
compressed_len = em->block_len; compressed_len = em->block_len;
cb = kmalloc(compressed_bio_size(fs_info, compressed_len), GFP_NOFS); cb = kmalloc(compressed_bio_size(fs_info, compressed_len), GFP_NOFS);
if (!cb) if (!cb) {
ret = BLK_STS_RESOURCE;
goto out; goto out;
}
refcount_set(&cb->pending_sectors, compressed_len >> fs_info->sectorsize_bits); refcount_set(&cb->pending_sectors, compressed_len >> fs_info->sectorsize_bits);
cb->status = BLK_STS_OK; cb->status = BLK_STS_OK;
@ -854,8 +858,10 @@ blk_status_t btrfs_submit_compressed_read(struct inode *inode, struct bio *bio,
nr_pages = DIV_ROUND_UP(compressed_len, PAGE_SIZE); nr_pages = DIV_ROUND_UP(compressed_len, PAGE_SIZE);
cb->compressed_pages = kcalloc(nr_pages, sizeof(struct page *), cb->compressed_pages = kcalloc(nr_pages, sizeof(struct page *),
GFP_NOFS); GFP_NOFS);
if (!cb->compressed_pages) if (!cb->compressed_pages) {
ret = BLK_STS_RESOURCE;
goto fail1; goto fail1;
}
for (pg_index = 0; pg_index < nr_pages; pg_index++) { for (pg_index = 0; pg_index < nr_pages; pg_index++) {
cb->compressed_pages[pg_index] = alloc_page(GFP_NOFS); cb->compressed_pages[pg_index] = alloc_page(GFP_NOFS);
@ -941,7 +947,7 @@ blk_status_t btrfs_submit_compressed_read(struct inode *inode, struct bio *bio,
comp_bio = NULL; comp_bio = NULL;
} }
} }
return 0; return BLK_STS_OK;
fail2: fail2:
while (faili >= 0) { while (faili >= 0) {
@ -954,6 +960,8 @@ blk_status_t btrfs_submit_compressed_read(struct inode *inode, struct bio *bio,
kfree(cb); kfree(cb);
out: out:
free_extent_map(em); free_extent_map(em);
bio->bi_status = ret;
bio_endio(bio);
return ret; return ret;
finish_cb: finish_cb:
if (comp_bio) { if (comp_bio) {

8
fs/btrfs/inode.c
View file

@ -2543,10 +2543,15 @@ blk_status_t btrfs_submit_data_bio(struct inode *inode, struct bio *bio,
goto out; goto out;
if (bio_flags & EXTENT_BIO_COMPRESSED) { if (bio_flags & EXTENT_BIO_COMPRESSED) {
/*
* btrfs_submit_compressed_read will handle completing
* the bio if there were any errors, so just return
* here.
*/
ret = btrfs_submit_compressed_read(inode, bio, ret = btrfs_submit_compressed_read(inode, bio,
mirror_num, mirror_num,
bio_flags); bio_flags);
goto out; goto out_no_endio;
} else { } else {
/* /*
* Lookup bio sums does extra checks around whether we * Lookup bio sums does extra checks around whether we
@ -2580,6 +2585,7 @@ blk_status_t btrfs_submit_data_bio(struct inode *inode, struct bio *bio,
bio->bi_status = ret; bio->bi_status = ret;
bio_endio(bio); bio_endio(bio);
} }
out_no_endio:
return ret; return ret;
} }