diff options
| author | Amir Goldstein <amir73il@gmail.com> | 2025-06-02 19:17:02 +0200 |
|---|---|---|
| committer | Kent Overstreet <kent.overstreet@linux.dev> | 2025-06-30 17:52:47 -0400 |
| commit | d4328c0933650ff39c03256e677f6beef12fde23 (patch) | |
| tree | 0931621bd58c1c5986db3129b3d146c45661c60e /fs/overlayfs/util.c | |
| parent | a865c674f8a66f61243af2af63cfd9cb219dbd79 (diff) | |
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>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Diffstat (limited to 'fs/overlayfs/util.c')
| -rw-r--r-- | fs/overlayfs/util.c | 15 |
1 files changed, 11 insertions, 4 deletions
diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c index dcccb4b4a66c..593c4da107d6 100644 --- a/fs/overlayfs/util.c +++ b/fs/overlayfs/util.c @@ -206,10 +206,17 @@ bool ovl_dentry_weird(struct dentry *dentry) if (!d_can_lookup(dentry) && !d_is_file(dentry) && !d_is_symlink(dentry)) return true; - return dentry->d_flags & (DCACHE_NEED_AUTOMOUNT | - DCACHE_MANAGE_TRANSIT | - DCACHE_OP_HASH | - DCACHE_OP_COMPARE); + if (dentry->d_flags & (DCACHE_NEED_AUTOMOUNT | DCACHE_MANAGE_TRANSIT)) + return true; + + /* + * Allow filesystems that are case-folding capable but deny composing + * ovl stack from case-folded directories. + */ + if (sb_has_encoding(dentry->d_sb)) + return IS_CASEFOLDED(d_inode(dentry)); + + return dentry->d_flags & (DCACHE_OP_HASH | DCACHE_OP_COMPARE); } enum ovl_path_type ovl_path_type(struct dentry *dentry) |