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authorTheodore Ts'o <tytso@mit.edu>2009-08-31 17:00:59 -0400
committerTheodore Ts'o <tytso@mit.edu>2009-08-31 17:00:59 -0400
commitde89de6e0cf4b1eb13f27137cf2aa40d287aabdf (patch)
treeb6429d327cb0a6985d3fd9bf11755353408ee44c
parent98a56ab382079f777e261e14512cbd4fb2107af4 (diff)
ext4: Restore wbc->range_start in ext4_da_writepages()
To solve a lock inversion problem, we implement part of the range_cyclic algorithm in ext4_da_writepages(). (See commit 2acf2c26 for more details.) As part of that change wbc->range_start was modified by ext4's writepages function, which causes its callers to get confused since they aren't expecting the filesystem to modify it. The simplest fix is to save and restore wbc->range_start in ext4_da_writepages. Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
-rw-r--r--fs/ext4/inode.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index d61fb523308..ff659e75757 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -2749,6 +2749,7 @@ static int ext4_da_writepages(struct address_space *mapping,
long pages_skipped;
int range_cyclic, cycled = 1, io_done = 0;
int needed_blocks, ret = 0, nr_to_writebump = 0;
+ loff_t range_start = wbc->range_start;
struct ext4_sb_info *sbi = EXT4_SB(mapping->host->i_sb);
trace_ext4_da_writepages(inode, wbc);
@@ -2917,6 +2918,7 @@ out_writepages:
if (!no_nrwrite_index_update)
wbc->no_nrwrite_index_update = 0;
wbc->nr_to_write -= nr_to_writebump;
+ wbc->range_start = range_start;
trace_ext4_da_writepages_result(inode, wbc, ret, pages_written);
return ret;
}