The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 70499cdfeb3625c87eebe4f7a7ea06fa7447e5df Mon Sep 17 00:00:00 2001
From: Bob Peterson rpeterso@redhat.com Date: Fri, 24 Jul 2020 12:06:31 -0500 Subject: [PATCH] gfs2: Never call gfs2_block_zero_range with an open transaction
Before this patch, some functions started transactions then they called gfs2_block_zero_range. However, gfs2_block_zero_range, like writes, can start transactions, which results in a recursive transaction error. For example:
do_shrink trunc_start gfs2_trans_begin <------------------------------------------------ gfs2_block_zero_range iomap_zero_range(inode, from, length, NULL, &gfs2_iomap_ops); iomap_apply ... iomap_zero_range_actor iomap_begin gfs2_iomap_begin gfs2_iomap_begin_write actor (iomap_zero_range_actor) iomap_zero iomap_write_begin gfs2_iomap_page_prepare gfs2_trans_begin <------------------------
This patch reorders the callers of gfs2_block_zero_range so that they only start their transactions after the call. It also adds a BUG_ON to ensure this doesn't happen again.
Fixes: 2257e468a63b ("gfs2: implement gfs2_block_zero_range using iomap_zero_range") Cc: stable@vger.kernel.org # v5.5+ Signed-off-by: Bob Peterson rpeterso@redhat.com Signed-off-by: Andreas Gruenbacher agruenba@redhat.com
diff --git a/fs/gfs2/bmap.c b/fs/gfs2/bmap.c index 6306eaae378b..6d2ea788d0a1 100644 --- a/fs/gfs2/bmap.c +++ b/fs/gfs2/bmap.c @@ -1351,9 +1351,15 @@ int gfs2_extent_map(struct inode *inode, u64 lblock, int *new, u64 *dblock, unsi return ret; }
+/* + * NOTE: Never call gfs2_block_zero_range with an open transaction because it + * uses iomap write to perform its actions, which begin their own transactions + * (iomap_begin, page_prepare, etc.) + */ static int gfs2_block_zero_range(struct inode *inode, loff_t from, unsigned int length) { + BUG_ON(current->journal_info); return iomap_zero_range(inode, from, length, NULL, &gfs2_iomap_ops); }
@@ -1414,6 +1420,16 @@ static int trunc_start(struct inode *inode, u64 newsize) u64 oldsize = inode->i_size; int error;
+ if (!gfs2_is_stuffed(ip)) { + unsigned int blocksize = i_blocksize(inode); + unsigned int offs = newsize & (blocksize - 1); + if (offs) { + error = gfs2_block_zero_range(inode, newsize, + blocksize - offs); + if (error) + return error; + } + } if (journaled) error = gfs2_trans_begin(sdp, RES_DINODE + RES_JDATA, GFS2_JTRUNC_REVOKES); else @@ -1427,19 +1443,10 @@ static int trunc_start(struct inode *inode, u64 newsize)
gfs2_trans_add_meta(ip->i_gl, dibh);
- if (gfs2_is_stuffed(ip)) { + if (gfs2_is_stuffed(ip)) gfs2_buffer_clear_tail(dibh, sizeof(struct gfs2_dinode) + newsize); - } else { - unsigned int blocksize = i_blocksize(inode); - unsigned int offs = newsize & (blocksize - 1); - if (offs) { - error = gfs2_block_zero_range(inode, newsize, - blocksize - offs); - if (error) - goto out; - } + else ip->i_diskflags |= GFS2_DIF_TRUNC_IN_PROG; - }
i_size_write(inode, newsize); ip->i_inode.i_mtime = ip->i_inode.i_ctime = current_time(&ip->i_inode); @@ -2448,25 +2455,7 @@ int __gfs2_punch_hole(struct file *file, loff_t offset, loff_t length) loff_t start, end; int error;
- start = round_down(offset, blocksize); - end = round_up(offset + length, blocksize) - 1; - error = filemap_write_and_wait_range(inode->i_mapping, start, end); - if (error) - return error; - - if (gfs2_is_jdata(ip)) - error = gfs2_trans_begin(sdp, RES_DINODE + 2 * RES_JDATA, - GFS2_JTRUNC_REVOKES); - else - error = gfs2_trans_begin(sdp, RES_DINODE, 0); - if (error) - return error; - - if (gfs2_is_stuffed(ip)) { - error = stuffed_zero_range(inode, offset, length); - if (error) - goto out; - } else { + if (!gfs2_is_stuffed(ip)) { unsigned int start_off, end_len;
start_off = offset & (blocksize - 1); @@ -2489,6 +2478,26 @@ int __gfs2_punch_hole(struct file *file, loff_t offset, loff_t length) } }
+ start = round_down(offset, blocksize); + end = round_up(offset + length, blocksize) - 1; + error = filemap_write_and_wait_range(inode->i_mapping, start, end); + if (error) + return error; + + if (gfs2_is_jdata(ip)) + error = gfs2_trans_begin(sdp, RES_DINODE + 2 * RES_JDATA, + GFS2_JTRUNC_REVOKES); + else + error = gfs2_trans_begin(sdp, RES_DINODE, 0); + if (error) + return error; + + if (gfs2_is_stuffed(ip)) { + error = stuffed_zero_range(inode, offset, length); + if (error) + goto out; + } + if (gfs2_is_jdata(ip)) { BUG_ON(!current->journal_info); gfs2_journaled_truncate_range(inode, offset, length);