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authorMatthew L. Creech <mlcreech@gmail.com>2011-03-04 17:55:02 -0500
committerArtem Bityutskiy <Artem.Bityutskiy@nokia.com>2011-03-11 10:52:07 +0200
commitd882962f6af2b484b62a7fb05ef959e1bf355fc4 (patch)
tree040a303908493e5edca3fe5c7aeecab2912bd3b0 /fs/ubifs/super.c
parent2765df7da540687c4d57ca840182122f074c5b9c (diff)
UBIFS: handle allocation failures in UBIFS write path
Running kernel 2.6.37, my PPC-based device occasionally gets an order-2 allocation failure in UBIFS, which causes the root FS to become unwritable: kswapd0: page allocation failure. order:2, mode:0x4050 Call Trace: [c787dc30] [c00085b8] show_stack+0x7c/0x194 (unreliable) [c787dc70] [c0061aec] __alloc_pages_nodemask+0x4f0/0x57c [c787dd00] [c0061b98] __get_free_pages+0x20/0x50 [c787dd10] [c00e4f88] ubifs_jnl_write_data+0x54/0x200 [c787dd50] [c00e82d4] do_writepage+0x94/0x198 [c787dd90] [c00675e4] shrink_page_list+0x40c/0x77c [c787de40] [c0067de0] shrink_inactive_list+0x1e0/0x370 [c787de90] [c0068224] shrink_zone+0x2b4/0x2b8 [c787df00] [c0068854] kswapd+0x408/0x5d4 [c787dfb0] [c0037bcc] kthread+0x80/0x84 [c787dff0] [c000ef44] kernel_thread+0x4c/0x68 Similar problems were encountered last April by Tomasz Stanislawski: http://patchwork.ozlabs.org/patch/50965/ This patch implements Artem's suggested fix: fall back to a mutex-protected static buffer, allocated at mount time. I tested it by forcing execution down the failure path, and didn't see any ill effects. Artem: massaged the patch a little, improved it so that we'd not allocate the write reserve buffer when we are in R/O mode. Signed-off-by: Matthew L. Creech <mlcreech@gmail.com> Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Diffstat (limited to 'fs/ubifs/super.c')
-rw-r--r--fs/ubifs/super.c18
1 files changed, 18 insertions, 0 deletions
diff --git a/fs/ubifs/super.c b/fs/ubifs/super.c
index d4b4cb4596e2..e360c7a71f9e 100644
--- a/fs/ubifs/super.c
+++ b/fs/ubifs/super.c
@@ -1213,6 +1213,13 @@ static int mount_ubifs(struct ubifs_info *c)
if (c->bulk_read == 1)
bu_init(c);
+ if (!c->ro_mount) {
+ c->write_reserve_buf = kmalloc(COMPRESSED_DATA_NODE_BUF_SZ,
+ GFP_KERNEL);
+ if (!c->write_reserve_buf)
+ goto out_free;
+ }
+
c->mounting = 1;
err = ubifs_read_superblock(c);
@@ -1482,6 +1489,7 @@ out_wbufs:
out_cbuf:
kfree(c->cbuf);
out_free:
+ kfree(c->write_reserve_buf);
kfree(c->bu.buf);
vfree(c->ileb_buf);
vfree(c->sbuf);
@@ -1520,6 +1528,7 @@ static void ubifs_umount(struct ubifs_info *c)
kfree(c->cbuf);
kfree(c->rcvrd_mst_node);
kfree(c->mst_node);
+ kfree(c->write_reserve_buf);
kfree(c->bu.buf);
vfree(c->ileb_buf);
vfree(c->sbuf);
@@ -1605,6 +1614,10 @@ static int ubifs_remount_rw(struct ubifs_info *c)
goto out;
}
+ c->write_reserve_buf = kmalloc(COMPRESSED_DATA_NODE_BUF_SZ, GFP_KERNEL);
+ if (!c->write_reserve_buf)
+ goto out;
+
err = ubifs_lpt_init(c, 0, 1);
if (err)
goto out;
@@ -1669,6 +1682,8 @@ out:
c->bgt = NULL;
}
free_wbufs(c);
+ kfree(c->write_reserve_buf);
+ c->write_reserve_buf = NULL;
vfree(c->ileb_buf);
c->ileb_buf = NULL;
ubifs_lpt_free(c, 1);
@@ -1712,6 +1727,8 @@ static void ubifs_remount_ro(struct ubifs_info *c)
free_wbufs(c);
vfree(c->orph_buf);
c->orph_buf = NULL;
+ kfree(c->write_reserve_buf);
+ c->write_reserve_buf = NULL;
vfree(c->ileb_buf);
c->ileb_buf = NULL;
ubifs_lpt_free(c, 1);
@@ -1942,6 +1959,7 @@ static int ubifs_fill_super(struct super_block *sb, void *data, int silent)
mutex_init(&c->mst_mutex);
mutex_init(&c->umount_mutex);
mutex_init(&c->bu_mutex);
+ mutex_init(&c->write_reserve_mutex);
init_waitqueue_head(&c->cmt_wq);
c->buds = RB_ROOT;
c->old_idx = RB_ROOT;