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btrfs: fix iomap_begin length for nocow writes

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commit 7833b86595 upstream.

can_nocow_extent can reduce the len passed in, which needs to be
propagated to btrfs_dio_iomap_begin so that iomap does not submit
more data then is mapped.

This problems exists since the btrfs_get_blocks_direct helper was added
in commit c5794e5178 ("btrfs: Factor out write portion of
btrfs_get_blocks_direct"), but the ordered_extent splitting added in
commit b73a6fd1b1 ("btrfs: split partial dio bios before submit")
added a WARN_ON that made a syzkaller test fail.

Reported-by: syzbot+ee90502d5c8fd1d0dd93@syzkaller.appspotmail.com
Fixes: c5794e5178 ("btrfs: Factor out write portion of btrfs_get_blocks_direct")
CC: stable@vger.kernel.org # 6.1+
Tested-by: syzbot+ee90502d5c8fd1d0dd93@syzkaller.appspotmail.com
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Christoph Hellwig
2023-06-08 11:10:25 +02:00
committed by Greg Kroah-Hartman
parent 4389fb6b6a
commit 4e9da0cda1
1 changed files with 12 additions and 6 deletions
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18
fs/btrfs/inode.c
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@@ -7387,7 +7387,7 @@ static struct extent_map *create_io_em(struct btrfs_inode *inode, u64 start,
static int btrfs_get_blocks_direct_write(struct extent_map **map, static int btrfs_get_blocks_direct_write(struct extent_map **map,
struct inode *inode, struct inode *inode,
struct btrfs_dio_data *dio_data, struct btrfs_dio_data *dio_data,
u64 start, u64 len, u64 start, u64 *lenp,
unsigned int iomap_flags) unsigned int iomap_flags)
{ {
const bool nowait = (iomap_flags & IOMAP_NOWAIT); const bool nowait = (iomap_flags & IOMAP_NOWAIT);
@@ -7398,6 +7398,7 @@ static int btrfs_get_blocks_direct_write(struct extent_map **map,
struct btrfs_block_group *bg; struct btrfs_block_group *bg;
bool can_nocow = false; bool can_nocow = false;
bool space_reserved = false; bool space_reserved = false;
u64 len = *lenp;
u64 prev_len; u64 prev_len;
int ret = 0; int ret = 0;
@@ -7468,15 +7469,19 @@ static int btrfs_get_blocks_direct_write(struct extent_map **map,
free_extent_map(em); free_extent_map(em);
*map = NULL; *map = NULL;
if (nowait) if (nowait) {
return -EAGAIN; ret = -EAGAIN;
goto out;
}
/* /*
* If we could not allocate data space before locking the file * If we could not allocate data space before locking the file
* range and we can't do a NOCOW write, then we have to fail. * range and we can't do a NOCOW write, then we have to fail.
*/ */
if (!dio_data->data_space_reserved) if (!dio_data->data_space_reserved) {
return -ENOSPC; ret = -ENOSPC;
goto out;
}
/* /*
* We have to COW and we have already reserved data space before, * We have to COW and we have already reserved data space before,
@@ -7517,6 +7522,7 @@ out:
btrfs_delalloc_release_extents(BTRFS_I(inode), len); btrfs_delalloc_release_extents(BTRFS_I(inode), len);
btrfs_delalloc_release_metadata(BTRFS_I(inode), len, true); btrfs_delalloc_release_metadata(BTRFS_I(inode), len, true);
} }
*lenp = len;
return ret; return ret;
} }
@@ -7693,7 +7699,7 @@ static int btrfs_dio_iomap_begin(struct inode *inode, loff_t start,
if (write) { if (write) {
ret = btrfs_get_blocks_direct_write(&em, inode, dio_data, ret = btrfs_get_blocks_direct_write(&em, inode, dio_data,
start, len, flags); start, &len, flags);
if (ret < 0) if (ret < 0)
goto unlock_err; goto unlock_err;
unlock_extents = true; unlock_extents = true;