[v3,2/6] fs, xfs: introduce FALLOC_FL_SEAL_BLOCK_MAP

Message ID	150243356799.8777.11625037981403766282.stgit@dwillia2-desk3.amr.corp.intel.com (mailing list archive)
State	New, archived
Headers	show Return-Path: <linux-xfs-owner@kernel.org> Subject: [PATCH v3 2/6] fs, xfs: introduce FALLOC_FL_SEAL_BLOCK_MAP From: Dan Williams <dan.j.williams@intel.com> To: darrick.wong@oracle.com Cc: Jan Kara <jack@suse.cz>, linux-nvdimm@lists.01.org, linux-api@vger.kernel.org, Dave Chinner <david@fromorbit.com>, linux-kernel@vger.kernel.org, linux-xfs@vger.kernel.org, Jeff Moyer <jmoyer@redhat.com>, Alexander Viro <viro@zeniv.linux.org.uk>, luto@kernel.org, linux-fsdevel@vger.kernel.org, Ross Zwisler <ross.zwisler@linux.intel.com>, Christoph Hellwig <hch@lst.de> Date: Thu, 10 Aug 2017 23:39:28 -0700 Message-ID: <150243356799.8777.11625037981403766282.stgit@dwillia2-desk3.amr.corp.intel.com> In-Reply-To: <150243355681.8777.14902834768886160223.stgit@dwillia2-desk3.amr.corp.intel.com> References: <150243355681.8777.14902834768886160223.stgit@dwillia2-desk3.amr.corp.intel.com> User-Agent: StGit/0.17.1-9-g687f MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-xfs-owner@vger.kernel.org Precedence: bulk

diff --git a/fs/open.c b/fs/open.c index 7395860d7164..76f57f7465c4 100644 --- a/fs/open.c +++ b/fs/open.c @@ -273,6 +273,17 @@ int vfs_fallocate(struct file *file, int mode, loff_t offset, loff_t len) (mode & ~(FALLOC_FL_UNSHARE_RANGE | FALLOC_FL_KEEP_SIZE))) return -EINVAL; + /* + * Seal block map operation should only be used exclusively, and + * with the IMMUTABLE capability. + */ + if (mode & FALLOC_FL_SEAL_BLOCK_MAP) { + if (!capable(CAP_LINUX_IMMUTABLE)) + return -EPERM; + if (mode & ~FALLOC_FL_SEAL_BLOCK_MAP) + return -EINVAL; + } + if (!(file->f_mode & FMODE_WRITE)) return -EBADF; @@ -292,9 +303,10 @@ int vfs_fallocate(struct file *file, int mode, loff_t offset, loff_t len) return -ETXTBSY; /* - * We cannot allow any allocation changes on an iomap immutable file + * We cannot allow any allocation changes on an iomap immutable file, + * but we can allow the fs to validate if this request is redundant. */ - if (IS_IOMAP_IMMUTABLE(inode)) + if (IS_IOMAP_IMMUTABLE(inode) && !(mode & FALLOC_FL_SEAL_BLOCK_MAP)) return -ETXTBSY; /* diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c index 8427b0003c79..2ac8f4ed5723 100644 --- a/fs/xfs/xfs_bmap_util.c +++ b/fs/xfs/xfs_bmap_util.c @@ -1390,6 +1390,78 @@ xfs_zero_file_space( } +int +xfs_seal_file_space( + struct xfs_inode *ip, + xfs_off_t offset, + xfs_off_t len) +{ + struct inode *inode = VFS_I(ip); + struct address_space *mapping = inode->i_mapping; + struct xfs_mount *mp = ip->i_mount; + uint blksize; + int error; + + ASSERT(xfs_isilocked(ip, XFS_IOLOCK_EXCL | XFS_MMAPLOCK_EXCL)); + + if (offset) + return -EINVAL; + + /* Before we unshare + allocate, validate if there is any work to do. */ + xfs_ilock(ip, XFS_ILOCK_EXCL); + error = -EINVAL; + if (len != i_size_read(inode)) + goto out_unlock; + + error = 0; + if (IS_IOMAP_IMMUTABLE(inode)) + goto out_unlock; + xfs_iunlock(ip, XFS_ILOCK_EXCL); + + + error = xfs_reflink_unshare(ip, offset, len); + if (error) + return error; + + blksize = 1 << mp->m_sb.sb_blocklog; + error = xfs_alloc_file_space(ip, round_down(offset, blksize), + round_up(offset + len, blksize) - + round_down(offset, blksize), + XFS_BMAPI_CONVERT | XFS_BMAPI_ZERO); + if (error) + return error; + + + xfs_ilock(ip, XFS_ILOCK_EXCL); + /* + * Did we race a size change? Note that since we hold the mmap + * and i/o locks we cannot race hole punch. + */ + error = -EINVAL; + if (len != i_size_read(inode)) + goto out_unlock; + + /* + * Allow DAX path to assume that the state of S_IOMAP_IMMUTABLE + * will never change while any mapping is established. + */ + error = -EBUSY; + if (mapping_mapped(mapping)) + goto out_unlock; + + /* Did we race someone attempting to share extents? */ + if (xfs_is_reflink_inode(ip)) + goto out_unlock; + + error = 0; + inode->i_flags |= S_IOMAP_IMMUTABLE; + +out_unlock: + xfs_iunlock(ip, XFS_ILOCK_EXCL); + + return error; +} + /* * @next_fsb will keep track of the extent currently undergoing shift. * @stop_fsb will keep track of the extent at which we have to stop. diff --git a/fs/xfs/xfs_bmap_util.h b/fs/xfs/xfs_bmap_util.h index 0cede1043571..5115a32a2483 100644 --- a/fs/xfs/xfs_bmap_util.h +++ b/fs/xfs/xfs_bmap_util.h @@ -60,6 +60,8 @@ int xfs_collapse_file_space(struct xfs_inode *, xfs_off_t offset, xfs_off_t len); int xfs_insert_file_space(struct xfs_inode *, xfs_off_t offset, xfs_off_t len); +int xfs_seal_file_space(struct xfs_inode *, xfs_off_t offset, + xfs_off_t len); /* EOF block manipulation functions */ bool xfs_can_free_eofblocks(struct xfs_inode *ip, bool force); diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c index c4893e226fd8..e21121530a90 100644 --- a/fs/xfs/xfs_file.c +++ b/fs/xfs/xfs_file.c @@ -739,7 +739,8 @@ xfs_file_write_iter( #define XFS_FALLOC_FL_SUPPORTED \ (FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE | \ FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_ZERO_RANGE | \ - FALLOC_FL_INSERT_RANGE | FALLOC_FL_UNSHARE_RANGE) + FALLOC_FL_INSERT_RANGE | FALLOC_FL_UNSHARE_RANGE | \ + FALLOC_FL_SEAL_BLOCK_MAP) STATIC long xfs_file_fallocate( @@ -834,9 +835,14 @@ xfs_file_fallocate( error = xfs_reflink_unshare(ip, offset, len); if (error) goto out_unlock; - } - error = xfs_alloc_file_space(ip, offset, len, - XFS_BMAPI_PREALLOC); + + error = xfs_alloc_file_space(ip, offset, len, + XFS_BMAPI_PREALLOC); + } else if (mode & FALLOC_FL_SEAL_BLOCK_MAP) { + error = xfs_seal_file_space(ip, offset, len); + } else + error = xfs_alloc_file_space(ip, offset, len, + XFS_BMAPI_PREALLOC); } if (error) goto out_unlock; diff --git a/include/linux/falloc.h b/include/linux/falloc.h index 7494dc67c66f..48546c6fbec7 100644 --- a/include/linux/falloc.h +++ b/include/linux/falloc.h @@ -26,6 +26,7 @@ struct space_resv { FALLOC_FL_COLLAPSE_RANGE | \ FALLOC_FL_ZERO_RANGE | \ FALLOC_FL_INSERT_RANGE | \ - FALLOC_FL_UNSHARE_RANGE) + FALLOC_FL_UNSHARE_RANGE | \ + FALLOC_FL_SEAL_BLOCK_MAP) #endif /* _FALLOC_H_ */ diff --git a/include/uapi/linux/falloc.h b/include/uapi/linux/falloc.h index b075f601919b..e3867cfe31d5 100644 --- a/include/uapi/linux/falloc.h +++ b/include/uapi/linux/falloc.h @@ -76,4 +76,21 @@ */ #define FALLOC_FL_UNSHARE_RANGE 0x40 +/* + * FALLOC_FL_SEAL_BLOCK_MAP is used to seal (make immutable) all of the + * file logical-to-physical extent offset mappings in the file. The + * purpose is to allow an application to assume that there are no holes + * or shared extents in the file and that the metadata needed to find + * all the physical extents of the file is stable and can never be + * dirtied. + * + * The immutable property is in effect for the entire inode, so the + * range for this operation must start at offset 0 and len must be + * greater than or equal to the current size of the file. If greater, + * this operation allocates, unshares, and seals in one atomic step. + * + * This flag implies FALLOC_FL_UNSHARE_RANGE and as such cannot be used + * with the punch, zero, collapse, or insert range modes. + */ +#define FALLOC_FL_SEAL_BLOCK_MAP 0x080 #endif /* _UAPI_FALLOC_H_ */

[v3,2/6] fs, xfs: introduce FALLOC_FL_SEAL_BLOCK_MAP

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