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| author | Dmitry Torokhov <dmitry.torokhov@gmail.com> | 2014-06-07 23:24:07 -0700 |
|---|---|---|
| committer | Dmitry Torokhov <dmitry.torokhov@gmail.com> | 2014-06-07 23:24:07 -0700 |
| commit | a292241cccb7e20e8b997a9a44177e7c98141859 (patch) | |
| tree | a0b0bb95e7dce3233a2d8b203f9e326cdec7a00e /fs/xfs/xfs_buf.c | |
| parent | d49cb7aeebb974713f9f7ab2991352d3050b095b (diff) | |
| parent | 68807a0c2015cb40df4869e16651f0ce5cc14d52 (diff) | |
Merge branch 'next' into for-linus
Prepare input updates for 3.16.
Diffstat (limited to 'fs/xfs/xfs_buf.c')
| -rw-r--r-- | fs/xfs/xfs_buf.c | 27 |
1 files changed, 23 insertions, 4 deletions
diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c index 9c061ef2b0d9..cb10a0aaab3a 100644 --- a/fs/xfs/xfs_buf.c +++ b/fs/xfs/xfs_buf.c @@ -396,7 +396,17 @@ _xfs_buf_map_pages( bp->b_addr = NULL; } else { int retried = 0; + unsigned noio_flag; + /* + * vm_map_ram() will allocate auxillary structures (e.g. + * pagetables) with GFP_KERNEL, yet we are likely to be under + * GFP_NOFS context here. Hence we need to tell memory reclaim + * that we are in such a context via PF_MEMALLOC_NOIO to prevent + * memory reclaim re-entering the filesystem here and + * potentially deadlocking. + */ + noio_flag = memalloc_noio_save(); do { bp->b_addr = vm_map_ram(bp->b_pages, bp->b_page_count, -1, PAGE_KERNEL); @@ -404,6 +414,7 @@ _xfs_buf_map_pages( break; vm_unmap_aliases(); } while (retried++ <= 1); + memalloc_noio_restore(noio_flag); if (!bp->b_addr) return -ENOMEM; @@ -1361,21 +1372,29 @@ xfs_buf_iorequest( xfs_buf_wait_unpin(bp); xfs_buf_hold(bp); - /* Set the count to 1 initially, this will stop an I/O + /* + * Set the count to 1 initially, this will stop an I/O * completion callout which happens before we have started * all the I/O from calling xfs_buf_ioend too early. */ atomic_set(&bp->b_io_remaining, 1); _xfs_buf_ioapply(bp); - _xfs_buf_ioend(bp, 1); + /* + * If _xfs_buf_ioapply failed, we'll get back here with + * only the reference we took above. _xfs_buf_ioend will + * drop it to zero, so we'd better not queue it for later, + * or we'll free it before it's done. + */ + _xfs_buf_ioend(bp, bp->b_error ? 0 : 1); xfs_buf_rele(bp); } /* * Waits for I/O to complete on the buffer supplied. It returns immediately if - * no I/O is pending or there is already a pending error on the buffer. It - * returns the I/O error code, if any, or 0 if there was no error. + * no I/O is pending or there is already a pending error on the buffer, in which + * case nothing will ever complete. It returns the I/O error code, if any, or + * 0 if there was no error. */ int xfs_buf_iowait( |