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author | Linus Torvalds <torvalds@linux-foundation.org> | 2010-05-27 10:43:44 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2010-05-27 10:43:44 -0700 |
commit | 105a048a4f35f7a74c7cc20b36dd83658b6ec232 (patch) | |
tree | 043b1110cda0042ba35d8aae59382bb094d0af3f /mm | |
parent | 00b9b0af5887fed54e899e3b7f5c2ccf5e739def (diff) | |
parent | 9aeead73782c4b8e2a91def36dbf95db28605c95 (diff) | |
download | lwn-105a048a4f35f7a74c7cc20b36dd83658b6ec232.tar.gz lwn-105a048a4f35f7a74c7cc20b36dd83658b6ec232.zip |
Merge git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable
* git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable: (27 commits)
Btrfs: add more error checking to btrfs_dirty_inode
Btrfs: allow unaligned DIO
Btrfs: drop verbose enospc printk
Btrfs: Fix block generation verification race
Btrfs: fix preallocation and nodatacow checks in O_DIRECT
Btrfs: avoid ENOSPC errors in btrfs_dirty_inode
Btrfs: move O_DIRECT space reservation to btrfs_direct_IO
Btrfs: rework O_DIRECT enospc handling
Btrfs: use async helpers for DIO write checksumming
Btrfs: don't walk around with task->state != TASK_RUNNING
Btrfs: do aio_write instead of write
Btrfs: add basic DIO read/write support
direct-io: do not merge logically non-contiguous requests
direct-io: add a hook for the fs to provide its own submit_bio function
fs: allow short direct-io reads to be completed via buffered IO
Btrfs: Metadata ENOSPC handling for balance
Btrfs: Pre-allocate space for data relocation
Btrfs: Metadata ENOSPC handling for tree log
Btrfs: Metadata reservation for orphan inodes
Btrfs: Introduce global metadata reservation
...
Diffstat (limited to 'mm')
-rw-r--r-- | mm/filemap.c | 36 |
1 files changed, 31 insertions, 5 deletions
diff --git a/mm/filemap.c b/mm/filemap.c index 35e12d186566..45a2d18df849 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -1275,7 +1275,7 @@ generic_file_aio_read(struct kiocb *iocb, const struct iovec *iov, { struct file *filp = iocb->ki_filp; ssize_t retval; - unsigned long seg; + unsigned long seg = 0; size_t count; loff_t *ppos = &iocb->ki_pos; @@ -1302,21 +1302,47 @@ generic_file_aio_read(struct kiocb *iocb, const struct iovec *iov, retval = mapping->a_ops->direct_IO(READ, iocb, iov, pos, nr_segs); } - if (retval > 0) + if (retval > 0) { *ppos = pos + retval; - if (retval) { + count -= retval; + } + + /* + * Btrfs can have a short DIO read if we encounter + * compressed extents, so if there was an error, or if + * we've already read everything we wanted to, or if + * there was a short read because we hit EOF, go ahead + * and return. Otherwise fallthrough to buffered io for + * the rest of the read. + */ + if (retval < 0 || !count || *ppos >= size) { file_accessed(filp); goto out; } } } + count = retval; for (seg = 0; seg < nr_segs; seg++) { read_descriptor_t desc; + loff_t offset = 0; + + /* + * If we did a short DIO read we need to skip the section of the + * iov that we've already read data into. + */ + if (count) { + if (count > iov[seg].iov_len) { + count -= iov[seg].iov_len; + continue; + } + offset = count; + count = 0; + } desc.written = 0; - desc.arg.buf = iov[seg].iov_base; - desc.count = iov[seg].iov_len; + desc.arg.buf = iov[seg].iov_base + offset; + desc.count = iov[seg].iov_len - offset; if (desc.count == 0) continue; desc.error = 0; |