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authorJie Liu <jeff.liu@oracle.com>2013-06-25 12:02:13 +0800
committerAl Viro <viro@zeniv.linux.org.uk>2013-07-03 16:23:27 +0400
commit46a1c2c7ae53de2a5676754b54a73c591a3951d2 (patch)
tree1910875cf34a7fe1cd8fd9474d3a5538236fb4f0 /fs/read_write.c
parent2142914e3eb1168978e842f65cfd182be7582861 (diff)
downloadlwn-46a1c2c7ae53de2a5676754b54a73c591a3951d2.tar.gz
lwn-46a1c2c7ae53de2a5676754b54a73c591a3951d2.zip
vfs: export lseek_execute() to modules
For those file systems(btrfs/ext4/ocfs2/tmpfs) that support SEEK_DATA/SEEK_HOLE functions, we end up handling the similar matter in lseek_execute() to update the current file offset to the desired offset if it is valid, ceph also does the simliar things at ceph_llseek(). To reduce the duplications, this patch make lseek_execute() public accessible so that we can call it directly from the underlying file systems. Thanks Dave Chinner for this suggestion. [AV: call it vfs_setpos(), don't bring the removed 'inode' argument back] v2->v1: - Add kernel-doc comments for lseek_execute() - Call lseek_execute() in ceph->llseek() Signed-off-by: Jie Liu <jeff.liu@oracle.com> Cc: Dave Chinner <dchinner@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andi Kleen <andi@firstfloor.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Christoph Hellwig <hch@lst.de> Cc: Chris Mason <chris.mason@fusionio.com> Cc: Josef Bacik <jbacik@fusionio.com> Cc: Ben Myers <bpm@sgi.com> Cc: Ted Tso <tytso@mit.edu> Cc: Hugh Dickins <hughd@google.com> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Joel Becker <jlbec@evilplan.org> Cc: Sage Weil <sage@inktank.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs/read_write.c')
-rw-r--r--fs/read_write.c19
1 files changed, 16 insertions, 3 deletions
diff --git a/fs/read_write.c b/fs/read_write.c
index 37d16e82b575..122a3846d9e1 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -41,7 +41,19 @@ static inline int unsigned_offsets(struct file *file)
return file->f_mode & FMODE_UNSIGNED_OFFSET;
}
-static loff_t lseek_execute(struct file *file, loff_t offset, loff_t maxsize)
+/**
+ * vfs_setpos - update the file offset for lseek
+ * @file: file structure in question
+ * @offset: file offset to seek to
+ * @maxsize: maximum file size
+ *
+ * This is a low-level filesystem helper for updating the file offset to
+ * the value specified by @offset if the given offset is valid and it is
+ * not equal to the current file offset.
+ *
+ * Return the specified offset on success and -EINVAL on invalid offset.
+ */
+loff_t vfs_setpos(struct file *file, loff_t offset, loff_t maxsize)
{
if (offset < 0 && !unsigned_offsets(file))
return -EINVAL;
@@ -54,6 +66,7 @@ static loff_t lseek_execute(struct file *file, loff_t offset, loff_t maxsize)
}
return offset;
}
+EXPORT_SYMBOL(vfs_setpos);
/**
* generic_file_llseek_size - generic llseek implementation for regular files
@@ -94,7 +107,7 @@ generic_file_llseek_size(struct file *file, loff_t offset, int whence,
* like SEEK_SET.
*/
spin_lock(&file->f_lock);
- offset = lseek_execute(file, file->f_pos + offset, maxsize);
+ offset = vfs_setpos(file, file->f_pos + offset, maxsize);
spin_unlock(&file->f_lock);
return offset;
case SEEK_DATA:
@@ -116,7 +129,7 @@ generic_file_llseek_size(struct file *file, loff_t offset, int whence,
break;
}
- return lseek_execute(file, offset, maxsize);
+ return vfs_setpos(file, offset, maxsize);
}
EXPORT_SYMBOL(generic_file_llseek_size);