From da1e90985a0e767e44397c9db0937e236033fa58 Mon Sep 17 00:00:00 2001 From: Joel Becker Date: Thu, 9 Oct 2008 17:20:29 -0700 Subject: ocfs2: Separate out sync reads from ocfs2_read_blocks() The ocfs2_read_blocks() function currently handles sync reads, cached, reads, and sometimes cached reads. We're going to add some functionality to it, so first we should simplify it. The uncached, synchronous reads are much easer to handle as a separate function, so we instroduce ocfs2_read_blocks_sync(). Signed-off-by: Joel Becker Signed-off-by: Mark Fasheh --- fs/ocfs2/buffer_head_io.c | 84 ++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 83 insertions(+), 1 deletion(-) (limited to 'fs/ocfs2/buffer_head_io.c') diff --git a/fs/ocfs2/buffer_head_io.c b/fs/ocfs2/buffer_head_io.c index f136639f5b41..ca4ab7ce85bf 100644 --- a/fs/ocfs2/buffer_head_io.c +++ b/fs/ocfs2/buffer_head_io.c @@ -66,7 +66,7 @@ int ocfs2_write_block(struct ocfs2_super *osb, struct buffer_head *bh, /* remove from dirty list before I/O. */ clear_buffer_dirty(bh); - get_bh(bh); /* for end_buffer_write_sync() */ + get_bh(bh); /* for end_buffer_write_sync() */ bh->b_end_io = end_buffer_write_sync; submit_bh(WRITE, bh); @@ -88,6 +88,88 @@ out: return ret; } +int ocfs2_read_blocks_sync(struct ocfs2_super *osb, u64 block, + unsigned int nr, struct buffer_head *bhs[]) +{ + int status = 0; + unsigned int i; + struct buffer_head *bh; + + if (!nr) { + mlog(ML_BH_IO, "No buffers will be read!\n"); + goto bail; + } + + for (i = 0 ; i < nr ; i++) { + if (bhs[i] == NULL) { + bhs[i] = sb_getblk(osb->sb, block++); + if (bhs[i] == NULL) { + status = -EIO; + mlog_errno(status); + goto bail; + } + } + bh = bhs[i]; + + if (buffer_jbd(bh)) { + mlog(ML_ERROR, + "trying to sync read a jbd " + "managed bh (blocknr = %llu), skipping\n", + (unsigned long long)bh->b_blocknr); + continue; + } + + if (buffer_dirty(bh)) { + /* This should probably be a BUG, or + * at least return an error. */ + mlog(ML_ERROR, + "trying to sync read a dirty " + "buffer! (blocknr = %llu), skipping\n", + (unsigned long long)bh->b_blocknr); + continue; + } + + lock_buffer(bh); + if (buffer_jbd(bh)) { + mlog(ML_ERROR, + "block %llu had the JBD bit set " + "while I was in lock_buffer!", + (unsigned long long)bh->b_blocknr); + BUG(); + } + + clear_buffer_uptodate(bh); + get_bh(bh); /* for end_buffer_read_sync() */ + bh->b_end_io = end_buffer_read_sync; + submit_bh(READ, bh); + } + + for (i = nr; i > 0; i--) { + bh = bhs[i - 1]; + + if (buffer_jbd(bh)) { + mlog(ML_ERROR, + "the journal got the buffer while it was " + "locked for io! (blocknr = %llu)\n", + (unsigned long long)bh->b_blocknr); + BUG(); + } + + wait_on_buffer(bh); + if (!buffer_uptodate(bh)) { + /* Status won't be cleared from here on out, + * so we can safely record this and loop back + * to cleanup the other buffers. */ + status = -EIO; + put_bh(bh); + bhs[i - 1] = NULL; + } + } + +bail: + return status; +} + int ocfs2_read_blocks(struct ocfs2_super *osb, u64 block, int nr, struct buffer_head *bhs[], int flags, struct inode *inode) -- cgit v1.2.3 From 31d33073ca38603dea705dae45e094a64ca062d6 Mon Sep 17 00:00:00 2001 From: Joel Becker Date: Thu, 9 Oct 2008 17:20:30 -0700 Subject: ocfs2: Require an inode for ocfs2_read_block(s)(). Now that synchronous readers are using ocfs2_read_blocks_sync(), all callers of ocfs2_read_blocks() are passing an inode. Use it unconditionally. Since it's there, we don't need to pass the ocfs2_super either. Signed-off-by: Joel Becker Signed-off-by: Mark Fasheh --- fs/ocfs2/buffer_head_io.c | 35 ++++++++++++----------------------- 1 file changed, 12 insertions(+), 23 deletions(-) (limited to 'fs/ocfs2/buffer_head_io.c') diff --git a/fs/ocfs2/buffer_head_io.c b/fs/ocfs2/buffer_head_io.c index ca4ab7ce85bf..718dbe5607ca 100644 --- a/fs/ocfs2/buffer_head_io.c +++ b/fs/ocfs2/buffer_head_io.c @@ -170,22 +170,20 @@ bail: return status; } -int ocfs2_read_blocks(struct ocfs2_super *osb, u64 block, int nr, - struct buffer_head *bhs[], int flags, - struct inode *inode) +int ocfs2_read_blocks(struct inode *inode, u64 block, int nr, + struct buffer_head *bhs[], int flags) { int status = 0; - struct super_block *sb; int i, ignore_cache = 0; struct buffer_head *bh; - mlog_entry("(block=(%llu), nr=(%d), flags=%d, inode=%p)\n", - (unsigned long long)block, nr, flags, inode); + mlog_entry("(inode=%p, block=(%llu), nr=(%d), flags=%d)\n", + inode, (unsigned long long)block, nr, flags); - BUG_ON((flags & OCFS2_BH_READAHEAD) && - (!inode || !(flags & OCFS2_BH_CACHED))); + BUG_ON(!inode); + BUG_ON((flags & OCFS2_BH_READAHEAD) && !(flags & OCFS2_BH_CACHED)); - if (osb == NULL || osb->sb == NULL || bhs == NULL) { + if (bhs == NULL) { status = -EINVAL; mlog_errno(status); goto bail; @@ -204,19 +202,12 @@ int ocfs2_read_blocks(struct ocfs2_super *osb, u64 block, int nr, goto bail; } - sb = osb->sb; - - if (flags & OCFS2_BH_CACHED && !inode) - flags &= ~OCFS2_BH_CACHED; - - if (inode) - mutex_lock(&OCFS2_I(inode)->ip_io_mutex); + mutex_lock(&OCFS2_I(inode)->ip_io_mutex); for (i = 0 ; i < nr ; i++) { if (bhs[i] == NULL) { - bhs[i] = sb_getblk(sb, block++); + bhs[i] = sb_getblk(inode->i_sb, block++); if (bhs[i] == NULL) { - if (inode) - mutex_unlock(&OCFS2_I(inode)->ip_io_mutex); + mutex_unlock(&OCFS2_I(inode)->ip_io_mutex); status = -EIO; mlog_errno(status); goto bail; @@ -347,11 +338,9 @@ int ocfs2_read_blocks(struct ocfs2_super *osb, u64 block, int nr, /* Always set the buffer in the cache, even if it was * a forced read, or read-ahead which hasn't yet * completed. */ - if (inode) - ocfs2_set_buffer_uptodate(inode, bh); + ocfs2_set_buffer_uptodate(inode, bh); } - if (inode) - mutex_unlock(&OCFS2_I(inode)->ip_io_mutex); + mutex_unlock(&OCFS2_I(inode)->ip_io_mutex); mlog(ML_BH_IO, "block=(%llu), nr=(%d), cached=%s, flags=0x%x\n", (unsigned long long)block, nr, -- cgit v1.2.3 From d4a8c93c8248534bdedb07f83c9aebd6f7d1d579 Mon Sep 17 00:00:00 2001 From: Joel Becker Date: Thu, 9 Oct 2008 17:20:34 -0700 Subject: ocfs2: Make cached block reads the common case. ocfs2_read_blocks() currently requires the CACHED flag for cached I/O. However, that's the common case. Let's flip it around and provide an IGNORE_CACHE flag for the special users. This has the added benefit of cleaning up the code some (ignore_cache takes on its special meaning earlier in the loop). Signed-off-by: Joel Becker Signed-off-by: Mark Fasheh --- fs/ocfs2/buffer_head_io.c | 19 +++++++++++-------- 1 file changed, 11 insertions(+), 8 deletions(-) (limited to 'fs/ocfs2/buffer_head_io.c') diff --git a/fs/ocfs2/buffer_head_io.c b/fs/ocfs2/buffer_head_io.c index 718dbe5607ca..7e947c672469 100644 --- a/fs/ocfs2/buffer_head_io.c +++ b/fs/ocfs2/buffer_head_io.c @@ -181,7 +181,8 @@ int ocfs2_read_blocks(struct inode *inode, u64 block, int nr, inode, (unsigned long long)block, nr, flags); BUG_ON(!inode); - BUG_ON((flags & OCFS2_BH_READAHEAD) && !(flags & OCFS2_BH_CACHED)); + BUG_ON((flags & OCFS2_BH_READAHEAD) && + (flags & OCFS2_BH_IGNORE_CACHE)); if (bhs == NULL) { status = -EINVAL; @@ -214,7 +215,7 @@ int ocfs2_read_blocks(struct inode *inode, u64 block, int nr, } } bh = bhs[i]; - ignore_cache = 0; + ignore_cache = (flags & OCFS2_BH_IGNORE_CACHE); /* There are three read-ahead cases here which we need to * be concerned with. All three assume a buffer has @@ -240,26 +241,27 @@ int ocfs2_read_blocks(struct inode *inode, u64 block, int nr, * before our is-it-in-flight check. */ - if (flags & OCFS2_BH_CACHED && - !ocfs2_buffer_uptodate(inode, bh)) { + if (!ignore_cache && !ocfs2_buffer_uptodate(inode, bh)) { mlog(ML_UPTODATE, "bh (%llu), inode %llu not uptodate\n", (unsigned long long)bh->b_blocknr, (unsigned long long)OCFS2_I(inode)->ip_blkno); + /* We're using ignore_cache here to say + * "go to disk" */ ignore_cache = 1; } /* XXX: Can we ever get this and *not* have the cached * flag set? */ if (buffer_jbd(bh)) { - if (!(flags & OCFS2_BH_CACHED) || ignore_cache) + if (ignore_cache) mlog(ML_BH_IO, "trying to sync read a jbd " "managed bh (blocknr = %llu)\n", (unsigned long long)bh->b_blocknr); continue; } - if (!(flags & OCFS2_BH_CACHED) || ignore_cache) { + if (ignore_cache) { if (buffer_dirty(bh)) { /* This should probably be a BUG, or * at least return an error. */ @@ -294,7 +296,7 @@ int ocfs2_read_blocks(struct inode *inode, u64 block, int nr, * previously read-ahead buffer may have * completed I/O while we were waiting for the * buffer lock. */ - if ((flags & OCFS2_BH_CACHED) + if (!(flags & OCFS2_BH_IGNORE_CACHE) && !(flags & OCFS2_BH_READAHEAD) && ocfs2_buffer_uptodate(inode, bh)) { unlock_buffer(bh); @@ -344,7 +346,8 @@ int ocfs2_read_blocks(struct inode *inode, u64 block, int nr, mlog(ML_BH_IO, "block=(%llu), nr=(%d), cached=%s, flags=0x%x\n", (unsigned long long)block, nr, - (!(flags & OCFS2_BH_CACHED) || ignore_cache) ? "no" : "yes", flags); + ((flags & OCFS2_BH_IGNORE_CACHE) || ignore_cache) ? "no" : "yes", + flags); bail: -- cgit v1.2.3