From 5f79ed685fc6122018c4b5826e2e5bdb7bc6f109 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Wed, 29 Apr 2009 10:50:48 -0400 Subject: [PATCH] xfs: a couple getbmap cleanups - reshuffle various conditionals for data vs attr fork to make the code more readable - do fine-grainded goto-based error handling - exit early from conditionals instead of keeping a long else branch around - allow kmem_alloc to fail Signed-off-by: Christoph Hellwig Reviewed-by: Eric Sandeen Reviewed-by: Felix Blyakher Signed-off-by: Felix Blyakher --- fs/xfs/xfs_bmap.c | 162 ++++++++++++++++++++++------------------------ 1 file changed, 79 insertions(+), 83 deletions(-) diff --git a/fs/xfs/xfs_bmap.c b/fs/xfs/xfs_bmap.c index 3a6ed426327a..abe42448b1c0 100644 --- a/fs/xfs/xfs_bmap.c +++ b/fs/xfs/xfs_bmap.c @@ -5880,7 +5880,7 @@ xfs_getbmap( void *arg) /* formatter arg */ { __int64_t bmvend; /* last block requested */ - int error; /* return value */ + int error = 0; /* return value */ __int64_t fixlen; /* length for -1 case */ int i; /* extent number */ int lock; /* lock state */ @@ -5899,30 +5899,8 @@ xfs_getbmap( mp = ip->i_mount; iflags = bmv->bmv_iflags; - whichfork = iflags & BMV_IF_ATTRFORK ? XFS_ATTR_FORK : XFS_DATA_FORK; - /* If the BMV_IF_NO_DMAPI_READ interface bit specified, do not - * generate a DMAPI read event. Otherwise, if the DM_EVENT_READ - * bit is set for the file, generate a read event in order - * that the DMAPI application may do its thing before we return - * the extents. Usually this means restoring user file data to - * regions of the file that look like holes. - * - * The "old behavior" (from XFS_IOC_GETBMAP) is to not specify - * BMV_IF_NO_DMAPI_READ so that read events are generated. - * If this were not true, callers of ioctl( XFS_IOC_GETBMAP ) - * could misinterpret holes in a DMAPI file as true holes, - * when in fact they may represent offline user data. - */ - if ((iflags & BMV_IF_NO_DMAPI_READ) == 0 && - DM_EVENT_ENABLED(ip, DM_EVENT_READ) && - whichfork == XFS_DATA_FORK) { - error = XFS_SEND_DATA(mp, DM_EVENT_READ, ip, 0, 0, 0, NULL); - if (error) - return XFS_ERROR(error); - } - if (whichfork == XFS_ATTR_FORK) { if (XFS_IFORK_Q(ip)) { if (ip->i_d.di_aformat != XFS_DINODE_FMT_EXTENTS && @@ -5936,11 +5914,37 @@ xfs_getbmap( ip->i_mount); return XFS_ERROR(EFSCORRUPTED); } - } else if (ip->i_d.di_format != XFS_DINODE_FMT_EXTENTS && - ip->i_d.di_format != XFS_DINODE_FMT_BTREE && - ip->i_d.di_format != XFS_DINODE_FMT_LOCAL) - return XFS_ERROR(EINVAL); - if (whichfork == XFS_DATA_FORK) { + + prealloced = 0; + fixlen = 1LL << 32; + } else { + /* + * If the BMV_IF_NO_DMAPI_READ interface bit specified, do + * not generate a DMAPI read event. Otherwise, if the + * DM_EVENT_READ bit is set for the file, generate a read + * event in order that the DMAPI application may do its thing + * before we return the extents. Usually this means restoring + * user file data to regions of the file that look like holes. + * + * The "old behavior" (from XFS_IOC_GETBMAP) is to not specify + * BMV_IF_NO_DMAPI_READ so that read events are generated. + * If this were not true, callers of ioctl(XFS_IOC_GETBMAP) + * could misinterpret holes in a DMAPI file as true holes, + * when in fact they may represent offline user data. + */ + if (DM_EVENT_ENABLED(ip, DM_EVENT_READ) && + !(iflags & BMV_IF_NO_DMAPI_READ)) { + error = XFS_SEND_DATA(mp, DM_EVENT_READ, ip, + 0, 0, 0, NULL); + if (error) + return XFS_ERROR(error); + } + + if (ip->i_d.di_format != XFS_DINODE_FMT_EXTENTS && + ip->i_d.di_format != XFS_DINODE_FMT_BTREE && + ip->i_d.di_format != XFS_DINODE_FMT_LOCAL) + return XFS_ERROR(EINVAL); + if (xfs_get_extsz_hint(ip) || ip->i_d.di_flags & (XFS_DIFLAG_PREALLOC|XFS_DIFLAG_APPEND)){ prealloced = 1; @@ -5949,42 +5953,34 @@ xfs_getbmap( prealloced = 0; fixlen = ip->i_size; } - } else { - prealloced = 0; - fixlen = 1LL << 32; } if (bmv->bmv_length == -1) { fixlen = XFS_FSB_TO_BB(mp, XFS_B_TO_FSB(mp, fixlen)); - bmv->bmv_length = MAX( (__int64_t)(fixlen - bmv->bmv_offset), - (__int64_t)0); - } else if (bmv->bmv_length < 0) - return XFS_ERROR(EINVAL); - if (bmv->bmv_length == 0) { + bmv->bmv_length = + max_t(__int64_t, fixlen - bmv->bmv_offset, 0); + } else if (bmv->bmv_length == 0) { bmv->bmv_entries = 0; return 0; + } else if (bmv->bmv_length < 0) { + return XFS_ERROR(EINVAL); } + nex = bmv->bmv_count - 1; if (nex <= 0) return XFS_ERROR(EINVAL); bmvend = bmv->bmv_offset + bmv->bmv_length; xfs_ilock(ip, XFS_IOLOCK_SHARED); - - if (((iflags & BMV_IF_DELALLOC) == 0) && - (whichfork == XFS_DATA_FORK) && - (ip->i_delayed_blks || ip->i_size > ip->i_d.di_size)) { - /* xfs_fsize_t last_byte = xfs_file_last_byte(ip); */ - error = xfs_flush_pages(ip, (xfs_off_t)0, - -1, 0, FI_REMAPF); - if (error) { - xfs_iunlock(ip, XFS_IOLOCK_SHARED); - return error; + if (whichfork == XFS_DATA_FORK && !(iflags & BMV_IF_DELALLOC)) { + if (ip->i_delayed_blks || ip->i_size > ip->i_d.di_size) { + error = xfs_flush_pages(ip, 0, -1, 0, FI_REMAPF); + if (error) + goto out_unlock_iolock; } - } - ASSERT(whichfork == XFS_ATTR_FORK || (iflags & BMV_IF_DELALLOC) || - ip->i_delayed_blks == 0); + ASSERT(ip->i_delayed_blks == 0); + } lock = xfs_ilock_map_shared(ip); @@ -5995,23 +5991,25 @@ xfs_getbmap( if (nex > XFS_IFORK_NEXTENTS(ip, whichfork) * 2 + 1) nex = XFS_IFORK_NEXTENTS(ip, whichfork) * 2 + 1; - bmapi_flags = xfs_bmapi_aflag(whichfork) | - ((iflags & BMV_IF_PREALLOC) ? 0 : XFS_BMAPI_IGSTATE); + bmapi_flags = xfs_bmapi_aflag(whichfork); + if (!(iflags & BMV_IF_PREALLOC)) + bmapi_flags |= XFS_BMAPI_IGSTATE; /* * Allocate enough space to handle "subnex" maps at a time. */ + error = ENOMEM; subnex = 16; - map = kmem_alloc(subnex * sizeof(*map), KM_SLEEP); + map = kmem_alloc(subnex * sizeof(*map), KM_MAYFAIL); + if (!map) + goto out_unlock_ilock; bmv->bmv_entries = 0; - if ((XFS_IFORK_NEXTENTS(ip, whichfork) == 0)) { - if (((iflags & BMV_IF_DELALLOC) == 0) || - whichfork == XFS_ATTR_FORK) { - error = 0; - goto unlock_and_return; - } + if (XFS_IFORK_NEXTENTS(ip, whichfork) == 0 && + (whichfork == XFS_ATTR_FORK || !(iflags & BMV_IF_DELALLOC))) { + error = 0; + goto out_free_map; } nexleft = nex; @@ -6023,10 +6021,12 @@ xfs_getbmap( bmapi_flags, NULL, 0, map, &nmap, NULL, NULL); if (error) - goto unlock_and_return; + goto out_free_map; ASSERT(nmap <= subnex); for (i = 0; i < nmap && nexleft && bmv->bmv_length; i++) { + int full = 0; /* user array is full */ + out.bmv_oflags = 0; if (map[i].br_state == XFS_EXT_UNWRITTEN) out.bmv_oflags |= BMV_OF_PREALLOC; @@ -6041,36 +6041,32 @@ xfs_getbmap( whichfork == XFS_ATTR_FORK) { /* came to the end of attribute fork */ out.bmv_oflags |= BMV_OF_LAST; - goto unlock_and_return; - } else { - int full = 0; /* user array is full */ - - if (!xfs_getbmapx_fix_eof_hole(ip, &out, - prealloced, bmvend, - map[i].br_startblock)) { - goto unlock_and_return; - } - - /* format results & advance arg */ - error = formatter(&arg, &out, &full); - if (error || full) - goto unlock_and_return; - nexleft--; - bmv->bmv_offset = - out.bmv_offset + out.bmv_length; - bmv->bmv_length = MAX((__int64_t)0, - (__int64_t)(bmvend - bmv->bmv_offset)); - bmv->bmv_entries++; + goto out_free_map; } + + if (!xfs_getbmapx_fix_eof_hole(ip, &out, prealloced, + bmvend, map[i].br_startblock)) + goto out_free_map; + + /* format results & advance arg */ + error = formatter(&arg, &out, &full); + if (error || full) + goto out_free_map; + nexleft--; + bmv->bmv_offset = + out.bmv_offset + out.bmv_length; + bmv->bmv_length = + max_t(__int64_t, 0, bmvend - bmv->bmv_offset); + bmv->bmv_entries++; } } while (nmap && nexleft && bmv->bmv_length); -unlock_and_return: + out_free_map: + kmem_free(map); + out_unlock_ilock: xfs_iunlock_map_shared(ip, lock); + out_unlock_iolock: xfs_iunlock(ip, XFS_IOLOCK_SHARED); - - kmem_free(map); - return error; } -- 2.20.1