iomap: reject delalloc mappings during writeback
Subsystems (2)
PATCH v2 1/1 iomap: reject delalloc mappings during writeback
From: Darrick J. Wong <[email protected]>
Filesystems should never provide a delayed allocation mapping to writeback; they're supposed to allocate the space before replying. This can lead to weird IO errors and crashes in the block layer if the filesystem is being malicious, or if it hadn't set iomap->dev because it's a delalloc mapping.
Fix this by failing writeback on delalloc mappings. Currently no filesystems actually misbehave in this manner, but we ought to be stricter about things like that.
---
v2: futureproof new iomap types
--- fs/iomap/ioend.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-)
fs/iomap/ioend.c +7 -6
@@ -215,17 +215,18 @@ ssize_t iomap_add_to_ioend(struct iomap_writepage_ctx *wpc, struct folio *folio,WARN_ON_ONCE (!folio->private && map_len < dirty_len);switch (wpc->iomap.type) { -case IOMAP_INLINE : -WARN_ON_ONCE (1 ); -return -EIO ; +case IOMAP_UNWRITTEN : + ioend_flags |=IOMAP_IOEND_UNWRITTEN ; +break ; +case IOMAP_MAPPED : +break ;case IOMAP_HOLE :return map_len;default : -break ; +WARN_ON_ONCE (1 ); +return -EIO ; } -if (wpc->iomap.type ==IOMAP_UNWRITTEN ) - ioend_flags |=IOMAP_IOEND_UNWRITTEN ;if (wpc->iomap.flags &IOMAP_F_SHARED ) ioend_flags |=IOMAP_IOEND_SHARED ;if (folio_test_dropbehind (folio))
Looks good:
Quoted 11 lines · Darrick J. Wong
From: Darrick J. Wong <[email protected]>
Filesystems should never provide a delayed allocation mapping to writeback; they're supposed to allocate the space before replying. This can lead to weird IO errors and crashes in the block layer if the filesystem is being malicious, or if it hadn't set
iomap->devbecause it's a delalloc mapping.Fix this by failing writeback on delalloc mappings. Currently no filesystems actually misbehave in this manner, but we ought to be stricter about things like that.
Looks good.
Quoted 40 lines
Cc <[email protected]> # v5.5Fixes 598ecfbaa742ac ("iomap: lift the xfs writeback code to iomap")Signed-off-by "Darrick J. Wong" <[email protected]>---
v2: futureproof new iomap types--- fs/iomap/ioend.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-)fs/iomap/ioend.c +7
-6@@ -215,17 +215,18 @@ ssize_t iomap_add_to_ioend(struct iomap_writepage_ctx *wpc, struct folio *folio,WARN_ON_ONCE (!folio->private && map_len < dirty_len);switch (wpc->iomap.type) { -case IOMAP_INLINE : -WARN_ON_ONCE (1 ); -return -EIO ; +case IOMAP_UNWRITTEN : + ioend_flags |=IOMAP_IOEND_UNWRITTEN ; +break ; +case IOMAP_MAPPED : +break ;case IOMAP_HOLE :return map_len;default : -break ; +WARN_ON_ONCE (1 ); +return -EIO ; } -if (wpc->iomap.type ==IOMAP_UNWRITTEN ) - ioend_flags |=IOMAP_IOEND_UNWRITTEN ;if (wpc->iomap.flags &IOMAP_F_SHARED ) ioend_flags |=IOMAP_IOEND_SHARED ;if (folio_test_dropbehind (folio))
PATCH v3 1/1 iomap: reject delalloc mappings during writeback
In reply to Darrick J. WongFrom: Darrick J. Wong <[email protected]>
Filesystems should never provide a delayed allocation mapping to writeback; they're supposed to allocate the space before replying. This can lead to weird IO errors and crashes in the block layer if the filesystem is being malicious, or if it hadn't set iomap->dev because it's a delalloc mapping.
Fix this by failing writeback on delalloc mappings. Currently no filesystems actually misbehave in this manner, but we ought to be stricter about things like that.
---
v3: add review tags
v2: futureproof new iomap types
--- fs/iomap/ioend.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-)
fs/iomap/ioend.c +7 -6
@@ -215,17 +215,18 @@ ssize_t iomap_add_to_ioend(struct iomap_writepage_ctx *wpc, struct folio *folio,WARN_ON_ONCE (!folio->private && map_len < dirty_len);switch (wpc->iomap.type) { -case IOMAP_INLINE : -WARN_ON_ONCE (1 ); -return -EIO ; +case IOMAP_UNWRITTEN : + ioend_flags |=IOMAP_IOEND_UNWRITTEN ; +break ; +case IOMAP_MAPPED : +break ;case IOMAP_HOLE :return map_len;default : -break ; +WARN_ON_ONCE (1 ); +return -EIO ; } -if (wpc->iomap.type ==IOMAP_UNWRITTEN ) - ioend_flags |=IOMAP_IOEND_UNWRITTEN ;if (wpc->iomap.flags &IOMAP_F_SHARED ) ioend_flags |=IOMAP_IOEND_SHARED ;if (folio_test_dropbehind (folio))
Quoted 11 lines · Darrick J. Wong
Filesystems should never provide a delayed allocation mapping to writeback; they're supposed to allocate the space before replying. This can lead to weird IO errors and crashes in the block layer if the filesystem is being malicious, or if it hadn't set
iomap->devbecause it's a delalloc mapping.Fix this by failing writeback on delalloc mappings. Currently no filesystems actually misbehave in this manner, but we ought to be stricter about things like that.
[...]
Applied to the vfs.fixes branch of the vfs/vfs.git tree. Patches in the vfs.fixes branch should appear in linux-next soon.
Please report any outstanding bugs that were missed during review in a new review to the original patch series allowing us to drop it.
It's encouraged to provide Acked-bys and Reviewed-bys even though the patch has now been applied. If possible patch trailers will be updated.
Note that commit hashes shown below are subject to change due to rebase, trailer updates or similar. If in doubt, please check the listed branch.
tree: https://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs.git branch: vfs.fixes
[1/1] iomap: reject delalloc mappings during writeback
https://git.kernel.org/vfs/vfs/c/d320f160aa5f