diff options
| author | Andreas Gruenbacher | 2026-02-05 15:52:57 +0100 |
|---|---|---|
| committer | Sasha Levin | 2026-03-04 07:20:32 -0500 |
| commit | e428670cfb2993d8c224effd076242ca6b0950de (patch) | |
| tree | c0e194a4c111033156630ba11ed7fa5ddece2da1 /fs | |
| parent | 048b58edc57dcd28b14757f00c554f108562e111 (diff) | |
gfs2: fiemap page fault fix
[ Upstream commit e411d74cc5ba290f85d0dd5e4d1df8f1d6d975d2 ]
In gfs2_fiemap(), we are calling iomap_fiemap() while holding the inode
glock. This can lead to recursive glock taking if the fiemap buffer is
memory mapped to the same inode and accessing it triggers a page fault.
Fix by disabling page faults for iomap_fiemap() and faulting in the
buffer by hand if necessary.
Fixes xfstest generic/742.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/gfs2/inode.c | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/fs/gfs2/inode.c b/fs/gfs2/inode.c index b65444bc1b5f..45040622d316 100644 --- a/fs/gfs2/inode.c +++ b/fs/gfs2/inode.c @@ -2105,6 +2105,14 @@ static int gfs2_getattr(struct mnt_idmap *idmap, return 0; } +static bool fault_in_fiemap(struct fiemap_extent_info *fi) +{ + struct fiemap_extent __user *dest = fi->fi_extents_start; + size_t size = sizeof(*dest) * fi->fi_extents_max; + + return fault_in_safe_writeable((char __user *)dest, size) == 0; +} + static int gfs2_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo, u64 start, u64 len) { @@ -2114,14 +2122,22 @@ static int gfs2_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo, inode_lock_shared(inode); +retry: ret = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, 0, &gh); if (ret) goto out; + pagefault_disable(); ret = iomap_fiemap(inode, fieinfo, start, len, &gfs2_iomap_ops); + pagefault_enable(); gfs2_glock_dq_uninit(&gh); + if (ret == -EFAULT && fault_in_fiemap(fieinfo)) { + fieinfo->fi_extents_mapped = 0; + goto retry; + } + out: inode_unlock_shared(inode); return ret; |