This is going to be used by overlayfs and possibly useful
for other filesystems.
Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx>
---
Documentation/filesystems/vfs.txt | 3 ++
include/linux/fs.h | 5 +++
mm/fadvise.c | 78 ++++++++++++++++++++++-----------------
3 files changed, 53 insertions(+), 33 deletions(-)
diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt
index e0ace944a0e1..4868fa9c0758 100644
--- a/Documentation/filesystems/vfs.txt
+++ b/Documentation/filesystems/vfs.txt
@@ -885,6 +885,7 @@ struct file_operations {
ssize_t (*copy_file_range)(struct file *, loff_t, struct file *, loff_t, size_t, unsigned int);
int (*clone_file_range)(struct file *, loff_t, struct file *, loff_t, u64);
int (*dedupe_file_range)(struct file *, loff_t, struct file *, loff_t, u64);
+ int (*fadvise)(struct file *, loff_t, loff_t, int);
};
Again, all methods are called without any locks being held, unless
@@ -965,6 +966,8 @@ otherwise noted.
dedupe_file_range: called by the ioctl(2) system call for FIDEDUPERANGE
command.
+ fadvise: possibly called by the fadvise64() system call.
+
Note that the file operations are implemented by the specific
filesystem in which the inode resides. When opening a device node
(character or block special) most filesystems will call special
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 33322702c910..6c0b4a1c22ff 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1763,6 +1763,7 @@ struct file_operations {
u64);
int (*dedupe_file_range)(struct file *, loff_t, struct file *, loff_t,
u64);
+ int (*fadvise)(struct file *, loff_t, loff_t, int);
} __randomize_layout;
struct inode_operations {
@@ -3459,4 +3460,8 @@ static inline bool dir_relax_shared(struct inode *inode)
extern bool path_noexec(const struct path *path);
extern void inode_nohighmem(struct inode *inode);
+/* mm/fadvise.c */
+extern int vfs_fadvise(struct file *file, loff_t offset, loff_t len,
+ int advice);
+
#endif /* _LINUX_FS_H */
diff --git a/mm/fadvise.c b/mm/fadvise.c
index 2d8376e3c640..2f59bac1cb77 100644
--- a/mm/fadvise.c
+++ b/mm/fadvise.c
@@ -27,9 +27,9 @@
* deactivate the pages and clear PG_Referenced.
*/
-int ksys_fadvise64_64(int fd, loff_t offset, loff_t len, int advice)
+static int generic_fadvise(struct file *file, loff_t offset, loff_t len,
+ int advice)
{
- struct fd f = fdget(fd);
struct inode *inode;
struct address_space *mapping;
struct backing_dev_info *bdi;
@@ -37,22 +37,14 @@ int ksys_fadvise64_64(int fd, loff_t offset, loff_t len, int advice)
pgoff_t start_index;
pgoff_t end_index;
unsigned long nrpages;
- int ret = 0;
- if (!f.file)
- return -EBADF;
+ inode = file_inode(file);
+ if (S_ISFIFO(inode->i_mode))
+ return -ESPIPE;
- inode = file_inode(f.file);
- if (S_ISFIFO(inode->i_mode)) {
- ret = -ESPIPE;
- goto out;
- }
-
- mapping = f.file->f_mapping;
- if (!mapping || len < 0) {
- ret = -EINVAL;
- goto out;
- }
+ mapping = file->f_mapping;
+ if (!mapping || len < 0)
+ return -EINVAL;
bdi = inode_to_bdi(mapping->host);
@@ -67,9 +59,9 @@ int ksys_fadvise64_64(int fd, loff_t offset, loff_t len, int advice)
/* no bad return value, but ignore advice */
break;
default:
- ret = -EINVAL;
+ return -EINVAL;
}
- goto out;
+ return 0;
}
/*
@@ -85,21 +77,21 @@ int ksys_fadvise64_64(int fd, loff_t offset, loff_t len, int advice)
switch (advice) {
case POSIX_FADV_NORMAL:
- f.file->f_ra.ra_pages = bdi->ra_pages;
- spin_lock(&f.file->f_lock);
- f.file->f_mode &= ~FMODE_RANDOM;
- spin_unlock(&f.file->f_lock);
+ file->f_ra.ra_pages = bdi->ra_pages;
+ spin_lock(&file->f_lock);
+ file->f_mode &= ~FMODE_RANDOM;
+ spin_unlock(&file->f_lock);
break;
case POSIX_FADV_RANDOM:
- spin_lock(&f.file->f_lock);
- f.file->f_mode |= FMODE_RANDOM;
- spin_unlock(&f.file->f_lock);
+ spin_lock(&file->f_lock);
+ file->f_mode |= FMODE_RANDOM;
+ spin_unlock(&file->f_lock);
break;
case POSIX_FADV_SEQUENTIAL:
- f.file->f_ra.ra_pages = bdi->ra_pages * 2;
- spin_lock(&f.file->f_lock);
- f.file->f_mode &= ~FMODE_RANDOM;
- spin_unlock(&f.file->f_lock);
+ file->f_ra.ra_pages = bdi->ra_pages * 2;
+ spin_lock(&file->f_lock);
+ file->f_mode &= ~FMODE_RANDOM;
+ spin_unlock(&file->f_lock);
break;
case POSIX_FADV_WILLNEED:
/* First and last PARTIAL page! */
@@ -115,8 +107,7 @@ int ksys_fadvise64_64(int fd, loff_t offset, loff_t len, int advice)
* Ignore return value because fadvise() shall return
* success even if filesystem can't retrieve a hint,
*/
- force_page_cache_readahead(mapping, f.file, start_index,
- nrpages);
+ force_page_cache_readahead(mapping, file, start_index, nrpages);
break;
case POSIX_FADV_NOREUSE:
break;
@@ -183,9 +174,30 @@ int ksys_fadvise64_64(int fd, loff_t offset, loff_t len, int advice)
}
break;
default:
- ret = -EINVAL;
+ return -EINVAL;
}
-out:
+ return 0;
+}
+
+int vfs_fadvise(struct file *file, loff_t offset, loff_t len, int advice)
+{
+ if (file->f_op->fadvise)
+ return file->f_op->fadvise(file, offset, len, advice);
+
+ return generic_fadvise(file, offset, len, advice);
+}
+EXPORT_SYMBOL(vfs_fadvise);
+
+int ksys_fadvise64_64(int fd, loff_t offset, loff_t len, int advice)
+{
+ struct fd f = fdget(fd);
+ int ret;
+
+ if (!f.file)
+ return -EBADF;
+
+ ret = vfs_fadvise(f.file, offset, len, advice);
+
fdput(f);
return ret;
}
--
2.7.4
