| Message ID | cover.1580251857.git.osandov@fb.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | fs: add flag to linkat() for replacing destination | expand |
From: Omar Sandoval <osandov@fb.com>
[Sorry if you got this twice, I botched the Cc's on the previous
submission.]
Hello,
This series adds an AT_LINK_REPLACE flag to linkat() which allows
atomically replacing the destination if it exists. This is a respin of
an old series [1] that I was convinced to resend due to some recent
interest [2][3].
Patch 1 adds a flags argument to i_ops->link() in preparation. Patch 2
adds the VFS support. Patch 3 fixes an inode leak in btrfs_link(),
included in this series because it conflicts with patch 4. Patch 4 adds
support for AT_LINK_REPLACE to Btrfs.
I've also included a man-page patch (with an example program), an xfs_io
patch, and an fstest.
Some outstanding issues:
- The Btrfs implementation does a d_drop() on the replaced dentry. We
probably want a d_replace() helper for filesystems to use.
- Should AT_LINK_REPLACE be limited to O_TMPFILE? In my opinion, the
answer is no. After all, `ln -f` is not that exotic.
- Should AT_LINK_REPLACE guarantee data integrity? Again, I think the
answer is no. That's more suited to something like Amir's AT_ATOMIC
proposal [4].
Changes since v3:
- Rebased on v5.5.
- Added patches 1 and 3.
- Incorporated Al's feedback on various error cases in patch 2.
- Renamed the flag to AT_LINK_REPLACE.
Thanks!
1: https://lore.kernel.org/linux-fsdevel/cover.1524549513.git.osandov@fb.com/
2: https://lore.kernel.org/linux-fsdevel/3326.1579019665@warthog.procyon.org.uk/
3: https://lore.kernel.org/linux-fsdevel/364531.1579265357@warthog.procyon.org.uk/
4: https://lore.kernel.org/linux-fsdevel/20190527172655.9287-1-amir73il@gmail.com/
Omar Sandoval (4):
fs: add flags argument to i_op->link()
fs: add AT_LINK_REPLACE flag for linkat() which replaces the target
Btrfs: fix inode reference count leak in btrfs_link() error path
Btrfs: add support for linkat() AT_REPLACE
fs/9p/vfs_inode.c | 5 +-
fs/9p/vfs_inode_dotl.c | 5 +-
fs/affs/affs.h | 2 +-
fs/affs/namei.c | 6 +-
fs/afs/dir.c | 7 +-
fs/bad_inode.c | 2 +-
fs/bfs/dir.c | 7 +-
fs/btrfs/inode.c | 70 ++++++++++++++--
fs/ceph/dir.c | 5 +-
fs/cifs/cifsfs.h | 2 +-
fs/cifs/link.c | 5 +-
fs/coda/dir.c | 5 +-
fs/ecryptfs/inode.c | 7 +-
fs/ext2/namei.c | 5 +-
fs/ext4/namei.c | 7 +-
fs/f2fs/namei.c | 5 +-
fs/fuse/dir.c | 5 +-
fs/gfs2/inode.c | 5 +-
fs/hfsplus/dir.c | 5 +-
fs/hostfs/hostfs_kern.c | 5 +-
fs/jffs2/dir.c | 8 +-
fs/jfs/namei.c | 7 +-
fs/libfs.c | 6 +-
fs/minix/namei.c | 5 +-
fs/namei.c | 166 +++++++++++++++++++++++++++++--------
fs/nfs/dir.c | 6 +-
fs/nfs/internal.h | 2 +-
fs/nfsd/vfs.c | 2 +-
fs/nilfs2/namei.c | 5 +-
fs/ocfs2/namei.c | 6 +-
fs/overlayfs/dir.c | 5 +-
fs/overlayfs/overlayfs.h | 2 +-
fs/reiserfs/namei.c | 5 +-
fs/sysv/namei.c | 7 +-
fs/ubifs/dir.c | 5 +-
fs/udf/namei.c | 5 +-
fs/ufs/namei.c | 5 +-
fs/xfs/xfs_iops.c | 6 +-
include/linux/fs.h | 6 +-
include/uapi/linux/fcntl.h | 1 +
mm/shmem.c | 6 +-
41 files changed, 341 insertions(+), 90 deletions(-)
From: Omar Sandoval <osandov@fb.com> Hello, This series adds an AT_LINK_REPLACE flag to linkat() which allows atomically replacing the destination if it exists. This is a respin of an old series [1] that I was convinced to resend due to some recent interest [2][3]. Patch 1 adds a flags argument to i_ops->link() in preparation. Patch 2 adds the VFS support. Patch 3 fixes an inode leak in btrfs_link(), included in this series because it conflicts with patch 4. Patch 4 adds support for AT_LINK_REPLACE to Btrfs. I've also included a man-page patch (with an example program), an xfs_io patch, and an fstest. Some outstanding issues: - The Btrfs implementation does a d_drop() on the replaced dentry. We probably want a d_replace() helper for filesystems to use. - Should AT_LINK_REPLACE be limited to O_TMPFILE? In my opinion, the answer is no. After all, `ln -f` is not that exotic. - Should AT_LINK_REPLACE guarantee data integrity? Again, I think the answer is no. That's more suited to something like Amir's AT_ATOMIC proposal [4]. Changes since v3: - Rebased on v5.5. - Added patches 1 and 3. - Incorporated Al's feedback on various error cases in patch 2. - Renamed the flag to AT_LINK_REPLACE. Thanks! 1: https://lore.kernel.org/linux-fsdevel/cover.1524549513.git.osandov@fb.com/ 2: https://lore.kernel.org/linux-fsdevel/3326.1579019665@warthog.procyon.org.uk/ 3: https://lore.kernel.org/linux-fsdevel/364531.1579265357@warthog.procyon.org.uk/ 4: https://lore.kernel.org/linux-fsdevel/20190527172655.9287-1-amir73il@gmail.com/ Cc: David Howells <dhowells@redhat.com> Cc: Amir Goldstein <amir73il@gmail.com> Cc: Xi Wang <xi@cs.washington.edu> Omar Sandoval (4): fs: add flags argument to i_op->link() fs: add AT_LINK_REPLACE flag for linkat() which replaces the target Btrfs: fix inode reference count leak in btrfs_link() error path Btrfs: add support for linkat() AT_REPLACE fs/9p/vfs_inode.c | 5 +- fs/9p/vfs_inode_dotl.c | 5 +- fs/affs/affs.h | 2 +- fs/affs/namei.c | 6 +- fs/afs/dir.c | 7 +- fs/bad_inode.c | 2 +- fs/bfs/dir.c | 7 +- fs/btrfs/inode.c | 70 ++++++++++++++-- fs/ceph/dir.c | 5 +- fs/cifs/cifsfs.h | 2 +- fs/cifs/link.c | 5 +- fs/coda/dir.c | 5 +- fs/ecryptfs/inode.c | 7 +- fs/ext2/namei.c | 5 +- fs/ext4/namei.c | 7 +- fs/f2fs/namei.c | 5 +- fs/fuse/dir.c | 5 +- fs/gfs2/inode.c | 5 +- fs/hfsplus/dir.c | 5 +- fs/hostfs/hostfs_kern.c | 5 +- fs/jffs2/dir.c | 8 +- fs/jfs/namei.c | 7 +- fs/libfs.c | 6 +- fs/minix/namei.c | 5 +- fs/namei.c | 166 +++++++++++++++++++++++++++++-------- fs/nfs/dir.c | 6 +- fs/nfs/internal.h | 2 +- fs/nfsd/vfs.c | 2 +- fs/nilfs2/namei.c | 5 +- fs/ocfs2/namei.c | 6 +- fs/overlayfs/dir.c | 5 +- fs/overlayfs/overlayfs.h | 2 +- fs/reiserfs/namei.c | 5 +- fs/sysv/namei.c | 7 +- fs/ubifs/dir.c | 5 +- fs/udf/namei.c | 5 +- fs/ufs/namei.c | 5 +- fs/xfs/xfs_iops.c | 6 +- include/linux/fs.h | 6 +- include/uapi/linux/fcntl.h | 1 + mm/shmem.c | 6 +- 41 files changed, 341 insertions(+), 90 deletions(-)