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| author | Amir Goldstein <amir73il@gmail.com> | 2025-06-02 19:17:02 +0200 |
|---|---|---|
| committer | Christian Brauner <brauner@kernel.org> | 2025-07-18 11:09:33 +0200 |
| commit | 083957f9614a8b2e284dbb3a85c5fec8e2fb26b8 (patch) | |
| tree | 90f6b2cc32486611c327a8f39948a628481651f8 /fs/overlayfs/params.c | |
| parent | Merge patch series "backing_file accessors cleanup" (diff) | |
| download | linux-083957f9614a8b2e284dbb3a85c5fec8e2fb26b8.tar.gz linux-083957f9614a8b2e284dbb3a85c5fec8e2fb26b8.zip | |
ovl: support layers on case-folding capable filesystems
Case folding is often applied to subtrees and not on an entire
filesystem.
Disallowing layers from filesystems that support case folding is over
limiting.
Replace the rule that case-folding capable are not allowed as layers
with a rule that case folded directories are not allowed in a merged
directory stack.
Should case folding be enabled on an underlying directory while
overlayfs is mounted the outcome is generally undefined.
Specifically in ovl_lookup(), we check the base underlying directory
and fail with -ESTALE and write a warning to kmsg if an underlying
directory case folding is enabled.
Suggested-by: Kent Overstreet <kent.overstreet@linux.dev>
Link: https://lore.kernel.org/linux-fsdevel/20250520051600.1903319-1-kent.overstreet@linux.dev/
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Link: https://lore.kernel.org/20250602171702.1941891-1-amir73il@gmail.com
Reviewed-by: Kent Overstreet <kent.overstreet@linux.dev>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Diffstat (limited to 'fs/overlayfs/params.c')
| -rw-r--r-- | fs/overlayfs/params.c | 10 |
1 files changed, 4 insertions, 6 deletions
diff --git a/fs/overlayfs/params.c b/fs/overlayfs/params.c index f42488c01957..2b9b31524c38 100644 --- a/fs/overlayfs/params.c +++ b/fs/overlayfs/params.c @@ -282,13 +282,11 @@ static int ovl_mount_dir_check(struct fs_context *fc, const struct path *path, return invalfc(fc, "%s is not a directory", name); /* - * Root dentries of case-insensitive capable filesystems might - * not have the dentry operations set, but still be incompatible - * with overlayfs. Check explicitly to prevent post-mount - * failures. + * Allow filesystems that are case-folding capable but deny composing + * ovl stack from case-folded directories. */ - if (sb_has_encoding(path->mnt->mnt_sb)) - return invalfc(fc, "case-insensitive capable filesystem on %s not supported", name); + if (ovl_dentry_casefolded(path->dentry)) + return invalfc(fc, "case-insensitive directory on %s not supported", name); if (ovl_dentry_weird(path->dentry)) return invalfc(fc, "filesystem on %s not supported", name); |