From 8aa7d37ebf2f0cfba1411acb34e7b40e73f653e7 Mon Sep 17 00:00:00 2001 From: Eric Sandeen Date: Mon, 8 Feb 2016 11:25:16 +1100 Subject: [PATCH] xfs: Factor xfs_seek_hole_data into helper Factor xfs_seek_hole_data into an unlocked helper which takes an xfs inode rather than a file for internal use. Also allow specification of "end" - the vfs lseek interface is defined such that any offset past eof/i_size shall return -ENXIO, but we will use this for quota code which does not maintain i_size, and we want to be able to SEEK_DATA past i_size as well. So the lseek path can send in i_size, and the quota code can determine its own ending offset. Signed-off-by: Eric Sandeen Reviewed-by: Dave Chinner Signed-off-by: Dave Chinner --- fs/xfs/xfs_file.c | 82 +++++++++++++++++++++++++++++++++++++----------------- fs/xfs/xfs_inode.h | 2 ++ 2 files changed, 59 insertions(+), 25 deletions(-) diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c index 52883ac..70a4b5a 100644 --- a/fs/xfs/xfs_file.c +++ b/fs/xfs/xfs_file.c @@ -1337,31 +1337,31 @@ out: return found; } -STATIC loff_t -xfs_seek_hole_data( - struct file *file, +/* + * caller must lock inode with xfs_ilock_data_map_shared, + * can we craft an appropriate ASSERT? + * + * end is because the VFS-level lseek interface is defined such that any + * offset past i_size shall return -ENXIO, but we use this for quota code + * which does not maintain i_size, and we want to SEEK_DATA past i_size. + */ +loff_t +__xfs_seek_hole_data( + struct inode *inode, loff_t start, + loff_t end, int whence) { - struct inode *inode = file->f_mapping->host; struct xfs_inode *ip = XFS_I(inode); struct xfs_mount *mp = ip->i_mount; loff_t uninitialized_var(offset); - xfs_fsize_t isize; xfs_fileoff_t fsbno; - xfs_filblks_t end; - uint lock; + xfs_filblks_t lastbno; int error; - if (XFS_FORCED_SHUTDOWN(mp)) - return -EIO; - - lock = xfs_ilock_data_map_shared(ip); - - isize = i_size_read(inode); - if (start >= isize) { + if (start >= end) { error = -ENXIO; - goto out_unlock; + goto out_error; } /* @@ -1369,22 +1369,22 @@ xfs_seek_hole_data( * by fsbno to the end block of the file. */ fsbno = XFS_B_TO_FSBT(mp, start); - end = XFS_B_TO_FSB(mp, isize); + lastbno = XFS_B_TO_FSB(mp, end); for (;;) { struct xfs_bmbt_irec map[2]; int nmap = 2; unsigned int i; - error = xfs_bmapi_read(ip, fsbno, end - fsbno, map, &nmap, + error = xfs_bmapi_read(ip, fsbno, lastbno - fsbno, map, &nmap, XFS_BMAPI_ENTIRE); if (error) - goto out_unlock; + goto out_error; /* No extents at given offset, must be beyond EOF */ if (nmap == 0) { error = -ENXIO; - goto out_unlock; + goto out_error; } for (i = 0; i < nmap; i++) { @@ -1426,7 +1426,7 @@ xfs_seek_hole_data( * hole at the end of any file). */ if (whence == SEEK_HOLE) { - offset = isize; + offset = end; break; } /* @@ -1434,7 +1434,7 @@ xfs_seek_hole_data( */ ASSERT(whence == SEEK_DATA); error = -ENXIO; - goto out_unlock; + goto out_error; } ASSERT(i > 1); @@ -1445,14 +1445,14 @@ xfs_seek_hole_data( */ fsbno = map[i - 1].br_startoff + map[i - 1].br_blockcount; start = XFS_FSB_TO_B(mp, fsbno); - if (start >= isize) { + if (start >= end) { if (whence == SEEK_HOLE) { - offset = isize; + offset = end; break; } ASSERT(whence == SEEK_DATA); error = -ENXIO; - goto out_unlock; + goto out_error; } } @@ -1464,7 +1464,39 @@ out: * situation in particular. */ if (whence == SEEK_HOLE) - offset = min_t(loff_t, offset, isize); + offset = min_t(loff_t, offset, end); + + return offset; + +out_error: + return error; +} + +STATIC loff_t +xfs_seek_hole_data( + struct file *file, + loff_t start, + int whence) +{ + struct inode *inode = file->f_mapping->host; + struct xfs_inode *ip = XFS_I(inode); + struct xfs_mount *mp = ip->i_mount; + uint lock; + loff_t offset, end; + int error = 0; + + if (XFS_FORCED_SHUTDOWN(mp)) + return -EIO; + + lock = xfs_ilock_data_map_shared(ip); + + end = i_size_read(inode); + offset = __xfs_seek_hole_data(inode, start, end, whence); + if (offset < 0) { + error = offset; + goto out_unlock; + } + offset = vfs_setpos(file, offset, inode->i_sb->s_maxbytes); out_unlock: diff --git a/fs/xfs/xfs_inode.h b/fs/xfs/xfs_inode.h index ca9e119..ed7e933 100644 --- a/fs/xfs/xfs_inode.h +++ b/fs/xfs/xfs_inode.h @@ -437,6 +437,8 @@ int xfs_update_prealloc_flags(struct xfs_inode *ip, int xfs_zero_eof(struct xfs_inode *ip, xfs_off_t offset, xfs_fsize_t isize, bool *did_zeroing); int xfs_iozero(struct xfs_inode *ip, loff_t pos, size_t count); +loff_t __xfs_seek_hole_data(struct inode *inode, loff_t start, + loff_t eof, int whence); /* from xfs_iops.c */ -- 2.7.4