diff options
| author | David Howells <dhowells@redhat.com> | 2015-01-29 12:02:28 +0000 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2015-02-22 11:38:38 -0500 |
| commit | df1a085af1f652a02238168c4f2b730c8c90dd4a (patch) | |
| tree | e9f269431a6ed4ec7a70de68cd9b62b0bcbe2dea | |
| parent | e7f7d2253c05143ed76ddc5e11f4cf0a9b814a27 (diff) | |
VFS: Add a fallthrough flag for marking virtual dentries
Add a DCACHE_FALLTHRU flag to indicate that, in a layered filesystem, this is
a virtual dentry that covers another one in a lower layer that should be used
instead. This may be recorded on medium if directory integration is stored
there.
The flag can be set with d_set_fallthru() and tested with d_is_fallthru().
Original-author: Valerie Aurora <vaurora@redhat.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| -rw-r--r-- | fs/dcache.c | 19 | ||||
| -rw-r--r-- | include/linux/dcache.h | 9 |
2 files changed, 27 insertions, 1 deletions
diff --git a/fs/dcache.c b/fs/dcache.c index dc400fd29f4..e33a0934efd 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -1659,6 +1659,22 @@ void d_set_d_op(struct dentry *dentry, const struct dentry_operations *op) } EXPORT_SYMBOL(d_set_d_op); + +/* + * d_set_fallthru - Mark a dentry as falling through to a lower layer + * @dentry - The dentry to mark + * + * Mark a dentry as falling through to the lower layer (as set with + * d_pin_lower()). This flag may be recorded on the medium. + */ +void d_set_fallthru(struct dentry *dentry) +{ + spin_lock(&dentry->d_lock); + dentry->d_flags |= DCACHE_FALLTHRU; + spin_unlock(&dentry->d_lock); +} +EXPORT_SYMBOL(d_set_fallthru); + static unsigned d_flags_for_inode(struct inode *inode) { unsigned add_flags = DCACHE_FILE_TYPE; @@ -1691,7 +1707,8 @@ static void __d_instantiate(struct dentry *dentry, struct inode *inode) unsigned add_flags = d_flags_for_inode(inode); spin_lock(&dentry->d_lock); - __d_set_type(dentry, add_flags); + dentry->d_flags &= ~(DCACHE_ENTRY_TYPE | DCACHE_FALLTHRU); + dentry->d_flags |= add_flags; if (inode) hlist_add_head(&dentry->d_u.d_alias, &inode->i_dentry); dentry->d_inode = inode; diff --git a/include/linux/dcache.h b/include/linux/dcache.h index 98d2a948a08..728f5d31b5e 100644 --- a/include/linux/dcache.h +++ b/include/linux/dcache.h @@ -223,6 +223,7 @@ struct dentry_operations { #define DCACHE_FILE_TYPE 0x00500000 /* Other file type (or fallthru to such) */ #define DCACHE_MAY_FREE 0x00800000 +#define DCACHE_FALLTHRU 0x01000000 /* Fall through to lower layer */ extern seqlock_t rename_lock; @@ -470,6 +471,14 @@ static inline bool d_is_positive(const struct dentry *dentry) return !d_is_negative(dentry); } +extern void d_set_fallthru(struct dentry *dentry); + +static inline bool d_is_fallthru(const struct dentry *dentry) +{ + return dentry->d_flags & DCACHE_FALLTHRU; +} + + extern int sysctl_vfs_cache_pressure; static inline unsigned long vfs_pressure_ratio(unsigned long val) |