[PATCH 46/64] cachefiles: Mark a backing file in use with an inode flag
From: David Howells <dhowells@redhat.com>
Date: 2021-11-29 14:35:59
Also in:
ceph-devel, linux-cifs, linux-fsdevel, lkml
Subsystem:
cachefiles: fs-cache backend for caching on mounted filesystems, filesystems (vfs and infrastructure), the rest · Maintainers:
David Howells, Alexander Viro, Christian Brauner, Linus Torvalds
Use an inode flag, S_KERNEL_FILE, to mark that a backing file is in use by the kernel to prevent cachefiles or other kernel services from interfering with that file. Using S_SWAPFILE instead isn't really viable as that has other effects in the I/O paths. Signed-off-by: David Howells <dhowells@redhat.com> --- fs/cachefiles/internal.h | 2 ++ fs/cachefiles/namei.c | 35 +++++++++++++++++++++++++++++++++++ 2 files changed, 37 insertions(+)
diff --git a/fs/cachefiles/internal.h b/fs/cachefiles/internal.h
index fbb38d3e6cac..ebb39373716b 100644
--- a/fs/cachefiles/internal.h
+++ b/fs/cachefiles/internal.h@@ -187,6 +187,8 @@ extern struct kmem_cache *cachefiles_object_jar; /* * namei.c */ +extern void cachefiles_unmark_inode_in_use(struct cachefiles_object *object, + struct file *file); extern struct dentry *cachefiles_get_directory(struct cachefiles_cache *cache, struct dentry *dir, const char *name);
diff --git a/fs/cachefiles/namei.c b/fs/cachefiles/namei.c
index 25ca41952dab..2e209e403713 100644
--- a/fs/cachefiles/namei.c
+++ b/fs/cachefiles/namei.c@@ -32,6 +32,18 @@ static bool __cachefiles_mark_inode_in_use(struct cachefiles_object *object, return can_use; } +static bool cachefiles_mark_inode_in_use(struct cachefiles_object *object, + struct dentry *dentry) +{ + struct inode *inode = d_backing_inode(dentry); + bool can_use; + + inode_lock(inode); + can_use = __cachefiles_mark_inode_in_use(object, dentry); + inode_unlock(inode); + return can_use; +} + /* * Unmark a backing inode. The caller must hold the inode lock. */
@@ -44,6 +56,29 @@ static void __cachefiles_unmark_inode_in_use(struct cachefiles_object *object, trace_cachefiles_mark_inactive(object, inode); } +/* + * Unmark a backing inode and tell cachefilesd that there's something that can + * be culled. + */ +void cachefiles_unmark_inode_in_use(struct cachefiles_object *object, + struct file *file) +{ + struct cachefiles_cache *cache = object->volume->cache; + struct inode *inode = file_inode(file); + + if (inode) { + inode_lock(inode); + __cachefiles_unmark_inode_in_use(object, file->f_path.dentry); + inode_unlock(inode); + + if (!test_bit(CACHEFILES_OBJECT_USING_TMPFILE, &object->flags)) { + atomic_long_add(inode->i_blocks, &cache->b_released); + if (atomic_inc_return(&cache->f_released)) + cachefiles_state_changed(cache); + } + } +} + /* * get a subdirectory */